--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/env/lib/python3.7/site-packages/soupsieve/css_match.py	Sat May 02 07:14:21 2020 -0400
@@ -0,0 +1,1497 @@
+"""CSS matcher."""
+from datetime import datetime
+from . import util
+import re
+from .import css_types as ct
+import unicodedata
+
+# Empty tag pattern (whitespace okay)
+RE_NOT_EMPTY = re.compile('[^ \t\r\n\f]')
+
+RE_NOT_WS = re.compile('[^ \t\r\n\f]+')
+
+# Relationships
+REL_PARENT = ' '
+REL_CLOSE_PARENT = '>'
+REL_SIBLING = '~'
+REL_CLOSE_SIBLING = '+'
+
+# Relationships for :has() (forward looking)
+REL_HAS_PARENT = ': '
+REL_HAS_CLOSE_PARENT = ':>'
+REL_HAS_SIBLING = ':~'
+REL_HAS_CLOSE_SIBLING = ':+'
+
+NS_XHTML = 'http://www.w3.org/1999/xhtml'
+NS_XML = 'http://www.w3.org/XML/1998/namespace'
+
+DIR_FLAGS = ct.SEL_DIR_LTR | ct.SEL_DIR_RTL
+RANGES = ct.SEL_IN_RANGE | ct.SEL_OUT_OF_RANGE
+
+DIR_MAP = {
+    'ltr': ct.SEL_DIR_LTR,
+    'rtl': ct.SEL_DIR_RTL,
+    'auto': 0
+}
+
+RE_NUM = re.compile(r"^(?P<value>-?(?:[0-9]{1,}(\.[0-9]+)?|\.[0-9]+))$")
+RE_TIME = re.compile(r'^(?P<hour>[0-9]{2}):(?P<minutes>[0-9]{2})$')
+RE_MONTH = re.compile(r'^(?P<year>[0-9]{4,})-(?P<month>[0-9]{2})$')
+RE_WEEK = re.compile(r'^(?P<year>[0-9]{4,})-W(?P<week>[0-9]{2})$')
+RE_DATE = re.compile(r'^(?P<year>[0-9]{4,})-(?P<month>[0-9]{2})-(?P<day>[0-9]{2})$')
+RE_DATETIME = re.compile(
+    r'^(?P<year>[0-9]{4,})-(?P<month>[0-9]{2})-(?P<day>[0-9]{2})T(?P<hour>[0-9]{2}):(?P<minutes>[0-9]{2})$'
+)
+RE_WILD_STRIP = re.compile(r'(?:(?:-\*-)(?:\*(?:-|$))*|-\*$)')
+
+MONTHS_30 = (4, 6, 9, 11)  # April, June, September, and November
+FEB = 2
+SHORT_MONTH = 30
+LONG_MONTH = 31
+FEB_MONTH = 28
+FEB_LEAP_MONTH = 29
+DAYS_IN_WEEK = 7
+
+
+class _FakeParent(object):
+    """
+    Fake parent class.
+
+    When we have a fragment with no `BeautifulSoup` document object,
+    we can't evaluate `nth` selectors properly.  Create a temporary
+    fake parent so we can traverse the root element as a child.
+    """
+
+    def __init__(self, element):
+        """Initialize."""
+
+        self.contents = [element]
+
+    def __len__(self):
+        """Length."""
+
+        return len(self.contents)
+
+
+class _DocumentNav(object):
+    """Navigate a Beautiful Soup document."""
+
+    @classmethod
+    def assert_valid_input(cls, tag):
+        """Check if valid input tag or document."""
+
+        # Fail on unexpected types.
+        if not cls.is_tag(tag):
+            raise TypeError("Expected a BeautifulSoup 'Tag', but instead recieved type {}".format(type(tag)))
+
+    @staticmethod
+    def is_doc(obj):
+        """Is `BeautifulSoup` object."""
+
+        import bs4
+        return isinstance(obj, bs4.BeautifulSoup)
+
+    @staticmethod
+    def is_tag(obj):
+        """Is tag."""
+
+        import bs4
+        return isinstance(obj, bs4.Tag)
+
+    @staticmethod
+    def is_declaration(obj):  # pragma: no cover
+        """Is declaration."""
+
+        import bs4
+        return isinstance(obj, bs4.Declaration)
+
+    @staticmethod
+    def is_cdata(obj):
+        """Is CDATA."""
+
+        import bs4
+        return isinstance(obj, bs4.CData)
+
+    @staticmethod
+    def is_processing_instruction(obj):  # pragma: no cover
+        """Is processing instruction."""
+
+        import bs4
+        return isinstance(obj, bs4.ProcessingInstruction)
+
+    @staticmethod
+    def is_navigable_string(obj):
+        """Is navigable string."""
+
+        import bs4
+        return isinstance(obj, bs4.NavigableString)
+
+    @staticmethod
+    def is_special_string(obj):
+        """Is special string."""
+
+        import bs4
+        return isinstance(obj, (bs4.Comment, bs4.Declaration, bs4.CData, bs4.ProcessingInstruction, bs4.Doctype))
+
+    @classmethod
+    def is_content_string(cls, obj):
+        """Check if node is content string."""
+
+        return cls.is_navigable_string(obj) and not cls.is_special_string(obj)
+
+    @staticmethod
+    def create_fake_parent(el):
+        """Create fake parent for a given element."""
+
+        return _FakeParent(el)
+
+    @staticmethod
+    def is_xml_tree(el):
+        """Check if element (or document) is from a XML tree."""
+
+        return el._is_xml
+
+    def is_iframe(self, el):
+        """Check if element is an `iframe`."""
+
+        return ((el.name if self.is_xml_tree(el) else util.lower(el.name)) == 'iframe') and self.is_html_tag(el)
+
+    def is_root(self, el):
+        """
+        Return whether element is a root element.
+
+        We check that the element is the root of the tree (which we have already pre-calculated),
+        and we check if it is the root element under an `iframe`.
+        """
+
+        root = self.root and self.root is el
+        if not root:
+            parent = self.get_parent(el)
+            root = parent is not None and self.is_html and self.is_iframe(parent)
+        return root
+
+    def get_contents(self, el, no_iframe=False):
+        """Get contents or contents in reverse."""
+        if not no_iframe or not self.is_iframe(el):
+            for content in el.contents:
+                yield content
+
+    def get_children(self, el, start=None, reverse=False, tags=True, no_iframe=False):
+        """Get children."""
+
+        if not no_iframe or not self.is_iframe(el):
+            last = len(el.contents) - 1
+            if start is None:
+                index = last if reverse else 0
+            else:
+                index = start
+            end = -1 if reverse else last + 1
+            incr = -1 if reverse else 1
+
+            if 0 <= index <= last:
+                while index != end:
+                    node = el.contents[index]
+                    index += incr
+                    if not tags or self.is_tag(node):
+                        yield node
+
+    def get_descendants(self, el, tags=True, no_iframe=False):
+        """Get descendants."""
+
+        if not no_iframe or not self.is_iframe(el):
+            next_good = None
+            for child in el.descendants:
+
+                if next_good is not None:
+                    if child is not next_good:
+                        continue
+                    next_good = None
+
+                is_tag = self.is_tag(child)
+
+                if no_iframe and is_tag and self.is_iframe(child):
+                    if child.next_sibling is not None:
+                        next_good = child.next_sibling
+                    else:
+                        last_child = child
+                        while self.is_tag(last_child) and last_child.contents:
+                            last_child = last_child.contents[-1]
+                        next_good = last_child.next_element
+                    yield child
+                    if next_good is None:
+                        break
+                    # Coverage isn't seeing this even though it's executed
+                    continue  # pragma: no cover
+
+                if not tags or is_tag:
+                    yield child
+
+    def get_parent(self, el, no_iframe=False):
+        """Get parent."""
+
+        parent = el.parent
+        if no_iframe and parent is not None and self.is_iframe(parent):
+            parent = None
+        return parent
+
+    @staticmethod
+    def get_tag_name(el):
+        """Get tag."""
+
+        return el.name
+
+    @staticmethod
+    def get_prefix_name(el):
+        """Get prefix."""
+
+        return el.prefix
+
+    @staticmethod
+    def get_uri(el):
+        """Get namespace `URI`."""
+
+        return el.namespace
+
+    @classmethod
+    def get_next(cls, el, tags=True):
+        """Get next sibling tag."""
+
+        sibling = el.next_sibling
+        while tags and not cls.is_tag(sibling) and sibling is not None:
+            sibling = sibling.next_sibling
+        return sibling
+
+    @classmethod
+    def get_previous(cls, el, tags=True):
+        """Get previous sibling tag."""
+
+        sibling = el.previous_sibling
+        while tags and not cls.is_tag(sibling) and sibling is not None:
+            sibling = sibling.previous_sibling
+        return sibling
+
+    @staticmethod
+    def has_html_ns(el):
+        """
+        Check if element has an HTML namespace.
+
+        This is a bit different than whether a element is treated as having an HTML namespace,
+        like we do in the case of `is_html_tag`.
+        """
+
+        ns = getattr(el, 'namespace') if el else None
+        return ns and ns == NS_XHTML
+
+    @staticmethod
+    def split_namespace(el, attr_name):
+        """Return namespace and attribute name without the prefix."""
+
+        return getattr(attr_name, 'namespace', None), getattr(attr_name, 'name', None)
+
+    @staticmethod
+    def get_attribute_by_name(el, name, default=None):
+        """Get attribute by name."""
+
+        value = default
+        if el._is_xml:
+            try:
+                value = el.attrs[name]
+            except KeyError:
+                pass
+        else:
+            for k, v in el.attrs.items():
+                if util.lower(k) == name:
+                    value = v
+                    break
+        return value
+
+    @staticmethod
+    def iter_attributes(el):
+        """Iterate attributes."""
+
+        for k, v in el.attrs.items():
+            yield k, v
+
+    @classmethod
+    def get_classes(cls, el):
+        """Get classes."""
+
+        classes = cls.get_attribute_by_name(el, 'class', [])
+        if isinstance(classes, str):
+            classes = RE_NOT_WS.findall(classes)
+        return classes
+
+    def get_text(self, el, no_iframe=False):
+        """Get text."""
+
+        return ''.join(
+            [node for node in self.get_descendants(el, tags=False, no_iframe=no_iframe) if self.is_content_string(node)]
+        )
+
+
+class Inputs(object):
+    """Class for parsing and validating input items."""
+
+    @staticmethod
+    def validate_day(year, month, day):
+        """Validate day."""
+
+        max_days = LONG_MONTH
+        if month == FEB:
+            max_days = FEB_LEAP_MONTH if ((year % 4 == 0) and (year % 100 != 0)) or (year % 400 == 0) else FEB_MONTH
+        elif month in MONTHS_30:
+            max_days = SHORT_MONTH
+        return 1 <= day <= max_days
+
+    @staticmethod
+    def validate_week(year, week):
+        """Validate week."""
+
+        max_week = datetime.strptime("{}-{}-{}".format(12, 31, year), "%m-%d-%Y").isocalendar()[1]
+        if max_week == 1:
+            max_week = 53
+        return 1 <= week <= max_week
+
+    @staticmethod
+    def validate_month(month):
+        """Validate month."""
+
+        return 1 <= month <= 12
+
+    @staticmethod
+    def validate_year(year):
+        """Validate year."""
+
+        return 1 <= year
+
+    @staticmethod
+    def validate_hour(hour):
+        """Validate hour."""
+
+        return 0 <= hour <= 23
+
+    @staticmethod
+    def validate_minutes(minutes):
+        """Validate minutes."""
+
+        return 0 <= minutes <= 59
+
+    @classmethod
+    def parse_value(cls, itype, value):
+        """Parse the input value."""
+
+        parsed = None
+        if itype == "date":
+            m = RE_DATE.match(value)
+            if m:
+                year = int(m.group('year'), 10)
+                month = int(m.group('month'), 10)
+                day = int(m.group('day'), 10)
+                if cls.validate_year(year) and cls.validate_month(month) and cls.validate_day(year, month, day):
+                    parsed = (year, month, day)
+        elif itype == "month":
+            m = RE_MONTH.match(value)
+            if m:
+                year = int(m.group('year'), 10)
+                month = int(m.group('month'), 10)
+                if cls.validate_year(year) and cls.validate_month(month):
+                    parsed = (year, month)
+        elif itype == "week":
+            m = RE_WEEK.match(value)
+            if m:
+                year = int(m.group('year'), 10)
+                week = int(m.group('week'), 10)
+                if cls.validate_year(year) and cls.validate_week(year, week):
+                    parsed = (year, week)
+        elif itype == "time":
+            m = RE_TIME.match(value)
+            if m:
+                hour = int(m.group('hour'), 10)
+                minutes = int(m.group('minutes'), 10)
+                if cls.validate_hour(hour) and cls.validate_minutes(minutes):
+                    parsed = (hour, minutes)
+        elif itype == "datetime-local":
+            m = RE_DATETIME.match(value)
+            if m:
+                year = int(m.group('year'), 10)
+                month = int(m.group('month'), 10)
+                day = int(m.group('day'), 10)
+                hour = int(m.group('hour'), 10)
+                minutes = int(m.group('minutes'), 10)
+                if (
+                    cls.validate_year(year) and cls.validate_month(month) and cls.validate_day(year, month, day) and
+                    cls.validate_hour(hour) and cls.validate_minutes(minutes)
+                ):
+                    parsed = (year, month, day, hour, minutes)
+        elif itype in ("number", "range"):
+            m = RE_NUM.match(value)
+            if m:
+                parsed = float(m.group('value'))
+        return parsed
+
+
+class _Match(object):
+    """Perform CSS matching."""
+
+    def __init__(self, selectors, scope, namespaces, flags):
+        """Initialize."""
+
+        self.assert_valid_input(scope)
+        self.tag = scope
+        self.cached_meta_lang = []
+        self.cached_default_forms = []
+        self.cached_indeterminate_forms = []
+        self.selectors = selectors
+        self.namespaces = {} if namespaces is None else namespaces
+        self.flags = flags
+        self.iframe_restrict = False
+
+        # Find the root element for the whole tree
+        doc = scope
+        parent = self.get_parent(doc)
+        while parent:
+            doc = parent
+            parent = self.get_parent(doc)
+        root = None
+        if not self.is_doc(doc):
+            root = doc
+        else:
+            for child in self.get_children(doc):
+                root = child
+                break
+
+        self.root = root
+        self.scope = scope if scope is not doc else root
+        self.has_html_namespace = self.has_html_ns(root)
+
+        # A document can be both XML and HTML (XHTML)
+        self.is_xml = self.is_xml_tree(doc)
+        self.is_html = not self.is_xml or self.has_html_namespace
+
+    def supports_namespaces(self):
+        """Check if namespaces are supported in the HTML type."""
+
+        return self.is_xml or self.has_html_namespace
+
+    def get_tag_ns(self, el):
+        """Get tag namespace."""
+
+        if self.supports_namespaces():
+            namespace = ''
+            ns = self.get_uri(el)
+            if ns:
+                namespace = ns
+        else:
+            namespace = NS_XHTML
+        return namespace
+
+    def is_html_tag(self, el):
+        """Check if tag is in HTML namespace."""
+
+        return self.get_tag_ns(el) == NS_XHTML
+
+    def get_tag(self, el):
+        """Get tag."""
+
+        name = self.get_tag_name(el)
+        return util.lower(name) if name is not None and not self.is_xml else name
+
+    def get_prefix(self, el):
+        """Get prefix."""
+
+        prefix = self.get_prefix_name(el)
+        return util.lower(prefix) if prefix is not None and not self.is_xml else prefix
+
+    def find_bidi(self, el):
+        """Get directionality from element text."""
+
+        for node in self.get_children(el, tags=False):
+
+            # Analyze child text nodes
+            if self.is_tag(node):
+
+                # Avoid analyzing certain elements specified in the specification.
+                direction = DIR_MAP.get(util.lower(self.get_attribute_by_name(node, 'dir', '')), None)
+                if (
+                    self.get_tag(node) in ('bdi', 'script', 'style', 'textarea', 'iframe') or
+                    not self.is_html_tag(node) or
+                    direction is not None
+                ):
+                    continue  # pragma: no cover
+
+                # Check directionality of this node's text
+                value = self.find_bidi(node)
+                if value is not None:
+                    return value
+
+                # Direction could not be determined
+                continue  # pragma: no cover
+
+            # Skip `doctype` comments, etc.
+            if self.is_special_string(node):
+                continue
+
+            # Analyze text nodes for directionality.
+            for c in node:
+                bidi = unicodedata.bidirectional(c)
+                if bidi in ('AL', 'R', 'L'):
+                    return ct.SEL_DIR_LTR if bidi == 'L' else ct.SEL_DIR_RTL
+        return None
+
+    def extended_language_filter(self, lang_range, lang_tag):
+        """Filter the language tags."""
+
+        match = True
+        lang_range = RE_WILD_STRIP.sub('-', lang_range).lower()
+        ranges = lang_range.split('-')
+        subtags = lang_tag.lower().split('-')
+        length = len(ranges)
+        rindex = 0
+        sindex = 0
+        r = ranges[rindex]
+        s = subtags[sindex]
+
+        # Primary tag needs to match
+        if r != '*' and r != s:
+            match = False
+
+        rindex += 1
+        sindex += 1
+
+        # Match until we run out of ranges
+        while match and rindex < length:
+            r = ranges[rindex]
+            try:
+                s = subtags[sindex]
+            except IndexError:
+                # Ran out of subtags,
+                # but we still have ranges
+                match = False
+                continue
+
+            # Empty range
+            if not r:
+                match = False
+                continue
+
+            # Matched range
+            elif s == r:
+                rindex += 1
+
+            # Implicit wildcard cannot match
+            # singletons
+            elif len(s) == 1:
+                match = False
+                continue
+
+            # Implicitly matched, so grab next subtag
+            sindex += 1
+
+        return match
+
+    def match_attribute_name(self, el, attr, prefix):
+        """Match attribute name and return value if it exists."""
+
+        value = None
+        if self.supports_namespaces():
+            value = None
+            # If we have not defined namespaces, we can't very well find them, so don't bother trying.
+            if prefix:
+                ns = self.namespaces.get(prefix)
+                if ns is None and prefix != '*':
+                    return None
+            else:
+                ns = None
+
+            for k, v in self.iter_attributes(el):
+
+                # Get attribute parts
+                namespace, name = self.split_namespace(el, k)
+
+                # Can't match a prefix attribute as we haven't specified one to match
+                # Try to match it normally as a whole `p:a` as selector may be trying `p\:a`.
+                if ns is None:
+                    if (self.is_xml and attr == k) or (not self.is_xml and util.lower(attr) == util.lower(k)):
+                        value = v
+                        break
+                    # Coverage is not finding this even though it is executed.
+                    # Adding a print statement before this (and erasing coverage) causes coverage to find the line.
+                    # Ignore the false positive message.
+                    continue  # pragma: no cover
+
+                # We can't match our desired prefix attribute as the attribute doesn't have a prefix
+                if namespace is None or ns != namespace and prefix != '*':
+                    continue
+
+                # The attribute doesn't match.
+                if (util.lower(attr) != util.lower(name)) if not self.is_xml else (attr != name):
+                    continue
+
+                value = v
+                break
+        else:
+            for k, v in self.iter_attributes(el):
+                if util.lower(attr) != util.lower(k):
+                    continue
+                value = v
+                break
+        return value
+
+    def match_namespace(self, el, tag):
+        """Match the namespace of the element."""
+
+        match = True
+        namespace = self.get_tag_ns(el)
+        default_namespace = self.namespaces.get('')
+        tag_ns = '' if tag.prefix is None else self.namespaces.get(tag.prefix, None)
+        # We must match the default namespace if one is not provided
+        if tag.prefix is None and (default_namespace is not None and namespace != default_namespace):
+            match = False
+        # If we specified `|tag`, we must not have a namespace.
+        elif (tag.prefix is not None and tag.prefix == '' and namespace):
+            match = False
+        # Verify prefix matches
+        elif (
+            tag.prefix and
+            tag.prefix != '*' and (tag_ns is None or namespace != tag_ns)
+        ):
+            match = False
+        return match
+
+    def match_attributes(self, el, attributes):
+        """Match attributes."""
+
+        match = True
+        if attributes:
+            for a in attributes:
+                value = self.match_attribute_name(el, a.attribute, a.prefix)
+                pattern = a.xml_type_pattern if self.is_xml and a.xml_type_pattern else a.pattern
+                if isinstance(value, list):
+                    value = ' '.join(value)
+                if value is None:
+                    match = False
+                    break
+                elif pattern is None:
+                    continue
+                elif pattern.match(value) is None:
+                    match = False
+                    break
+        return match
+
+    def match_tagname(self, el, tag):
+        """Match tag name."""
+
+        name = (util.lower(tag.name) if not self.is_xml and tag.name is not None else tag.name)
+        return not (
+            name is not None and
+            name not in (self.get_tag(el), '*')
+        )
+
+    def match_tag(self, el, tag):
+        """Match the tag."""
+
+        match = True
+        if tag is not None:
+            # Verify namespace
+            if not self.match_namespace(el, tag):
+                match = False
+            if not self.match_tagname(el, tag):
+                match = False
+        return match
+
+    def match_past_relations(self, el, relation):
+        """Match past relationship."""
+
+        found = False
+        if relation[0].rel_type == REL_PARENT:
+            parent = self.get_parent(el, no_iframe=self.iframe_restrict)
+            while not found and parent:
+                found = self.match_selectors(parent, relation)
+                parent = self.get_parent(parent, no_iframe=self.iframe_restrict)
+        elif relation[0].rel_type == REL_CLOSE_PARENT:
+            parent = self.get_parent(el, no_iframe=self.iframe_restrict)
+            if parent:
+                found = self.match_selectors(parent, relation)
+        elif relation[0].rel_type == REL_SIBLING:
+            sibling = self.get_previous(el)
+            while not found and sibling:
+                found = self.match_selectors(sibling, relation)
+                sibling = self.get_previous(sibling)
+        elif relation[0].rel_type == REL_CLOSE_SIBLING:
+            sibling = self.get_previous(el)
+            if sibling and self.is_tag(sibling):
+                found = self.match_selectors(sibling, relation)
+        return found
+
+    def match_future_child(self, parent, relation, recursive=False):
+        """Match future child."""
+
+        match = False
+        children = self.get_descendants if recursive else self.get_children
+        for child in children(parent, no_iframe=self.iframe_restrict):
+            match = self.match_selectors(child, relation)
+            if match:
+                break
+        return match
+
+    def match_future_relations(self, el, relation):
+        """Match future relationship."""
+
+        found = False
+        if relation[0].rel_type == REL_HAS_PARENT:
+            found = self.match_future_child(el, relation, True)
+        elif relation[0].rel_type == REL_HAS_CLOSE_PARENT:
+            found = self.match_future_child(el, relation)
+        elif relation[0].rel_type == REL_HAS_SIBLING:
+            sibling = self.get_next(el)
+            while not found and sibling:
+                found = self.match_selectors(sibling, relation)
+                sibling = self.get_next(sibling)
+        elif relation[0].rel_type == REL_HAS_CLOSE_SIBLING:
+            sibling = self.get_next(el)
+            if sibling and self.is_tag(sibling):
+                found = self.match_selectors(sibling, relation)
+        return found
+
+    def match_relations(self, el, relation):
+        """Match relationship to other elements."""
+
+        found = False
+
+        if relation[0].rel_type.startswith(':'):
+            found = self.match_future_relations(el, relation)
+        else:
+            found = self.match_past_relations(el, relation)
+
+        return found
+
+    def match_id(self, el, ids):
+        """Match element's ID."""
+
+        found = True
+        for i in ids:
+            if i != self.get_attribute_by_name(el, 'id', ''):
+                found = False
+                break
+        return found
+
+    def match_classes(self, el, classes):
+        """Match element's classes."""
+
+        current_classes = self.get_classes(el)
+        found = True
+        for c in classes:
+            if c not in current_classes:
+                found = False
+                break
+        return found
+
+    def match_root(self, el):
+        """Match element as root."""
+
+        is_root = self.is_root(el)
+        if is_root:
+            sibling = self.get_previous(el, tags=False)
+            while is_root and sibling is not None:
+                if (
+                    self.is_tag(sibling) or (self.is_content_string(sibling) and sibling.strip()) or
+                    self.is_cdata(sibling)
+                ):
+                    is_root = False
+                else:
+                    sibling = self.get_previous(sibling, tags=False)
+        if is_root:
+            sibling = self.get_next(el, tags=False)
+            while is_root and sibling is not None:
+                if (
+                    self.is_tag(sibling) or (self.is_content_string(sibling) and sibling.strip()) or
+                    self.is_cdata(sibling)
+                ):
+                    is_root = False
+                else:
+                    sibling = self.get_next(sibling, tags=False)
+        return is_root
+
+    def match_scope(self, el):
+        """Match element as scope."""
+
+        return self.scope is el
+
+    def match_nth_tag_type(self, el, child):
+        """Match tag type for `nth` matches."""
+
+        return(
+            (self.get_tag(child) == self.get_tag(el)) and
+            (self.get_tag_ns(child) == self.get_tag_ns(el))
+        )
+
+    def match_nth(self, el, nth):
+        """Match `nth` elements."""
+
+        matched = True
+
+        for n in nth:
+            matched = False
+            if n.selectors and not self.match_selectors(el, n.selectors):
+                break
+            parent = self.get_parent(el)
+            if parent is None:
+                parent = self.create_fake_parent(el)
+            last = n.last
+            last_index = len(parent) - 1
+            index = last_index if last else 0
+            relative_index = 0
+            a = n.a
+            b = n.b
+            var = n.n
+            count = 0
+            count_incr = 1
+            factor = -1 if last else 1
+            idx = last_idx = a * count + b if var else a
+
+            # We can only adjust bounds within a variable index
+            if var:
+                # Abort if our nth index is out of bounds and only getting further out of bounds as we increment.
+                # Otherwise, increment to try to get in bounds.
+                adjust = None
+                while idx < 1 or idx > last_index:
+                    if idx < 0:
+                        diff_low = 0 - idx
+                        if adjust is not None and adjust == 1:
+                            break
+                        adjust = -1
+                        count += count_incr
+                        idx = last_idx = a * count + b if var else a
+                        diff = 0 - idx
+                        if diff >= diff_low:
+                            break
+                    else:
+                        diff_high = idx - last_index
+                        if adjust is not None and adjust == -1:
+                            break
+                        adjust = 1
+                        count += count_incr
+                        idx = last_idx = a * count + b if var else a
+                        diff = idx - last_index
+                        if diff >= diff_high:
+                            break
+                        diff_high = diff
+
+                # If a < 0, our count is working backwards, so floor the index by increasing the count.
+                # Find the count that yields the lowest, in bound value and use that.
+                # Lastly reverse count increment so that we'll increase our index.
+                lowest = count
+                if a < 0:
+                    while idx >= 1:
+                        lowest = count
+                        count += count_incr
+                        idx = last_idx = a * count + b if var else a
+                    count_incr = -1
+                count = lowest
+                idx = last_idx = a * count + b if var else a
+
+            # Evaluate elements while our calculated nth index is still in range
+            while 1 <= idx <= last_index + 1:
+                child = None
+                # Evaluate while our child index is still in range.
+                for child in self.get_children(parent, start=index, reverse=factor < 0, tags=False):
+                    index += factor
+                    if not self.is_tag(child):
+                        continue
+                    # Handle `of S` in `nth-child`
+                    if n.selectors and not self.match_selectors(child, n.selectors):
+                        continue
+                    # Handle `of-type`
+                    if n.of_type and not self.match_nth_tag_type(el, child):
+                        continue
+                    relative_index += 1
+                    if relative_index == idx:
+                        if child is el:
+                            matched = True
+                        else:
+                            break
+                    if child is el:
+                        break
+                if child is el:
+                    break
+                last_idx = idx
+                count += count_incr
+                if count < 0:
+                    # Count is counting down and has now ventured into invalid territory.
+                    break
+                idx = a * count + b if var else a
+                if last_idx == idx:
+                    break
+            if not matched:
+                break
+        return matched
+
+    def match_empty(self, el):
+        """Check if element is empty (if requested)."""
+
+        is_empty = True
+        for child in self.get_children(el, tags=False):
+            if self.is_tag(child):
+                is_empty = False
+                break
+            elif self.is_content_string(child) and RE_NOT_EMPTY.search(child):
+                is_empty = False
+                break
+        return is_empty
+
+    def match_subselectors(self, el, selectors):
+        """Match selectors."""
+
+        match = True
+        for sel in selectors:
+            if not self.match_selectors(el, sel):
+                match = False
+        return match
+
+    def match_contains(self, el, contains):
+        """Match element if it contains text."""
+
+        match = True
+        content = None
+        for contain_list in contains:
+            if content is None:
+                content = self.get_text(el, no_iframe=self.is_html)
+            found = False
+            for text in contain_list.text:
+                if text in content:
+                    found = True
+                    break
+            if not found:
+                match = False
+        return match
+
+    def match_default(self, el):
+        """Match default."""
+
+        match = False
+
+        # Find this input's form
+        form = None
+        parent = self.get_parent(el, no_iframe=True)
+        while parent and form is None:
+            if self.get_tag(parent) == 'form' and self.is_html_tag(parent):
+                form = parent
+            else:
+                parent = self.get_parent(parent, no_iframe=True)
+
+        # Look in form cache to see if we've already located its default button
+        found_form = False
+        for f, t in self.cached_default_forms:
+            if f is form:
+                found_form = True
+                if t is el:
+                    match = True
+                break
+
+        # We didn't have the form cached, so look for its default button
+        if not found_form:
+            for child in self.get_descendants(form, no_iframe=True):
+                name = self.get_tag(child)
+                # Can't do nested forms (haven't figured out why we never hit this)
+                if name == 'form':  # pragma: no cover
+                    break
+                if name in ('input', 'button'):
+                    v = self.get_attribute_by_name(child, 'type', '')
+                    if v and util.lower(v) == 'submit':
+                        self.cached_default_forms.append([form, child])
+                        if el is child:
+                            match = True
+                        break
+        return match
+
+    def match_indeterminate(self, el):
+        """Match default."""
+
+        match = False
+        name = self.get_attribute_by_name(el, 'name')
+
+        def get_parent_form(el):
+            """Find this input's form."""
+            form = None
+            parent = self.get_parent(el, no_iframe=True)
+            while form is None:
+                if self.get_tag(parent) == 'form' and self.is_html_tag(parent):
+                    form = parent
+                    break
+                last_parent = parent
+                parent = self.get_parent(parent, no_iframe=True)
+                if parent is None:
+                    form = last_parent
+                    break
+            return form
+
+        form = get_parent_form(el)
+
+        # Look in form cache to see if we've already evaluated that its fellow radio buttons are indeterminate
+        found_form = False
+        for f, n, i in self.cached_indeterminate_forms:
+            if f is form and n == name:
+                found_form = True
+                if i is True:
+                    match = True
+                break
+
+        # We didn't have the form cached, so validate that the radio button is indeterminate
+        if not found_form:
+            checked = False
+            for child in self.get_descendants(form, no_iframe=True):
+                if child is el:
+                    continue
+                tag_name = self.get_tag(child)
+                if tag_name == 'input':
+                    is_radio = False
+                    check = False
+                    has_name = False
+                    for k, v in self.iter_attributes(child):
+                        if util.lower(k) == 'type' and util.lower(v) == 'radio':
+                            is_radio = True
+                        elif util.lower(k) == 'name' and v == name:
+                            has_name = True
+                        elif util.lower(k) == 'checked':
+                            check = True
+                        if is_radio and check and has_name and get_parent_form(child) is form:
+                            checked = True
+                            break
+                if checked:
+                    break
+            if not checked:
+                match = True
+            self.cached_indeterminate_forms.append([form, name, match])
+
+        return match
+
+    def match_lang(self, el, langs):
+        """Match languages."""
+
+        match = False
+        has_ns = self.supports_namespaces()
+        root = self.root
+        has_html_namespace = self.has_html_namespace
+
+        # Walk parents looking for `lang` (HTML) or `xml:lang` XML property.
+        parent = el
+        found_lang = None
+        last = None
+        while not found_lang:
+            has_html_ns = self.has_html_ns(parent)
+            for k, v in self.iter_attributes(parent):
+                attr_ns, attr = self.split_namespace(parent, k)
+                if (
+                    ((not has_ns or has_html_ns) and (util.lower(k) if not self.is_xml else k) == 'lang') or
+                    (
+                        has_ns and not has_html_ns and attr_ns == NS_XML and
+                        (util.lower(attr) if not self.is_xml and attr is not None else attr) == 'lang'
+                    )
+                ):
+                    found_lang = v
+                    break
+            last = parent
+            parent = self.get_parent(parent, no_iframe=self.is_html)
+
+            if parent is None:
+                root = last
+                has_html_namespace = self.has_html_ns(root)
+                parent = last
+                break
+
+        # Use cached meta language.
+        if not found_lang and self.cached_meta_lang:
+            for cache in self.cached_meta_lang:
+                if root is cache[0]:
+                    found_lang = cache[1]
+
+        # If we couldn't find a language, and the document is HTML, look to meta to determine language.
+        if found_lang is None and (not self.is_xml or (has_html_namespace and root.name == 'html')):
+            # Find head
+            found = False
+            for tag in ('html', 'head'):
+                found = False
+                for child in self.get_children(parent, no_iframe=self.is_html):
+                    if self.get_tag(child) == tag and self.is_html_tag(child):
+                        found = True
+                        parent = child
+                        break
+                if not found:  # pragma: no cover
+                    break
+
+            # Search meta tags
+            if found:
+                for child in parent:
+                    if self.is_tag(child) and self.get_tag(child) == 'meta' and self.is_html_tag(parent):
+                        c_lang = False
+                        content = None
+                        for k, v in self.iter_attributes(child):
+                            if util.lower(k) == 'http-equiv' and util.lower(v) == 'content-language':
+                                c_lang = True
+                            if util.lower(k) == 'content':
+                                content = v
+                            if c_lang and content:
+                                found_lang = content
+                                self.cached_meta_lang.append((root, found_lang))
+                                break
+                    if found_lang:
+                        break
+                if not found_lang:
+                    self.cached_meta_lang.append((root, False))
+
+        # If we determined a language, compare.
+        if found_lang:
+            for patterns in langs:
+                match = False
+                for pattern in patterns:
+                    if self.extended_language_filter(pattern, found_lang):
+                        match = True
+                if not match:
+                    break
+
+        return match
+
+    def match_dir(self, el, directionality):
+        """Check directionality."""
+
+        # If we have to match both left and right, we can't match either.
+        if directionality & ct.SEL_DIR_LTR and directionality & ct.SEL_DIR_RTL:
+            return False
+
+        if el is None or not self.is_html_tag(el):
+            return False
+
+        # Element has defined direction of left to right or right to left
+        direction = DIR_MAP.get(util.lower(self.get_attribute_by_name(el, 'dir', '')), None)
+        if direction not in (None, 0):
+            return direction == directionality
+
+        # Element is the document element (the root) and no direction assigned, assume left to right.
+        is_root = self.is_root(el)
+        if is_root and direction is None:
+            return ct.SEL_DIR_LTR == directionality
+
+        # If `input[type=telephone]` and no direction is assigned, assume left to right.
+        name = self.get_tag(el)
+        is_input = name == 'input'
+        is_textarea = name == 'textarea'
+        is_bdi = name == 'bdi'
+        itype = util.lower(self.get_attribute_by_name(el, 'type', '')) if is_input else ''
+        if is_input and itype == 'tel' and direction is None:
+            return ct.SEL_DIR_LTR == directionality
+
+        # Auto handling for text inputs
+        if ((is_input and itype in ('text', 'search', 'tel', 'url', 'email')) or is_textarea) and direction == 0:
+            if is_textarea:
+                value = []
+                for node in self.get_contents(el, no_iframe=True):
+                    if self.is_content_string(node):
+                        value.append(node)
+                value = ''.join(value)
+            else:
+                value = self.get_attribute_by_name(el, 'value', '')
+            if value:
+                for c in value:
+                    bidi = unicodedata.bidirectional(c)
+                    if bidi in ('AL', 'R', 'L'):
+                        direction = ct.SEL_DIR_LTR if bidi == 'L' else ct.SEL_DIR_RTL
+                        return direction == directionality
+                # Assume left to right
+                return ct.SEL_DIR_LTR == directionality
+            elif is_root:
+                return ct.SEL_DIR_LTR == directionality
+            return self.match_dir(self.get_parent(el, no_iframe=True), directionality)
+
+        # Auto handling for `bdi` and other non text inputs.
+        if (is_bdi and direction is None) or direction == 0:
+            direction = self.find_bidi(el)
+            if direction is not None:
+                return direction == directionality
+            elif is_root:
+                return ct.SEL_DIR_LTR == directionality
+            return self.match_dir(self.get_parent(el, no_iframe=True), directionality)
+
+        # Match parents direction
+        return self.match_dir(self.get_parent(el, no_iframe=True), directionality)
+
+    def match_range(self, el, condition):
+        """
+        Match range.
+
+        Behavior is modeled after what we see in browsers. Browsers seem to evaluate
+        if the value is out of range, and if not, it is in range. So a missing value
+        will not evaluate out of range; therefore, value is in range. Personally, I
+        feel like this should evaluate as neither in or out of range.
+        """
+
+        out_of_range = False
+
+        itype = util.lower(self.get_attribute_by_name(el, 'type'))
+        mn = self.get_attribute_by_name(el, 'min', None)
+        if mn is not None:
+            mn = Inputs.parse_value(itype, mn)
+        mx = self.get_attribute_by_name(el, 'max', None)
+        if mx is not None:
+            mx = Inputs.parse_value(itype, mx)
+
+        # There is no valid min or max, so we cannot evaluate a range
+        if mn is None and mx is None:
+            return False
+
+        value = self.get_attribute_by_name(el, 'value', None)
+        if value is not None:
+            value = Inputs.parse_value(itype, value)
+        if value is not None:
+            if itype in ("date", "datetime-local", "month", "week", "number", "range"):
+                if mn is not None and value < mn:
+                    out_of_range = True
+                if not out_of_range and mx is not None and value > mx:
+                    out_of_range = True
+            elif itype == "time":
+                if mn is not None and mx is not None and mn > mx:
+                    # Time is periodic, so this is a reversed/discontinuous range
+                    if value < mn and value > mx:
+                        out_of_range = True
+                else:
+                    if mn is not None and value < mn:
+                        out_of_range = True
+                    if not out_of_range and mx is not None and value > mx:
+                        out_of_range = True
+
+        return not out_of_range if condition & ct.SEL_IN_RANGE else out_of_range
+
+    def match_defined(self, el):
+        """
+        Match defined.
+
+        `:defined` is related to custom elements in a browser.
+
+        - If the document is XML (not XHTML), all tags will match.
+        - Tags that are not custom (don't have a hyphen) are marked defined.
+        - If the tag has a prefix (without or without a namespace), it will not match.
+
+        This is of course requires the parser to provide us with the proper prefix and namespace info,
+        if it doesn't, there is nothing we can do.
+        """
+
+        name = self.get_tag(el)
+        return (
+            name.find('-') == -1 or
+            name.find(':') != -1 or
+            self.get_prefix(el) is not None
+        )
+
+    def match_placeholder_shown(self, el):
+        """
+        Match placeholder shown according to HTML spec.
+
+        - text area should be checked if they have content. A single newline does not count as content.
+
+        """
+
+        match = False
+        content = self.get_text(el)
+        if content in ('', '\n'):
+            match = True
+
+        return match
+
+    def match_selectors(self, el, selectors):
+        """Check if element matches one of the selectors."""
+
+        match = False
+        is_not = selectors.is_not
+        is_html = selectors.is_html
+
+        # Internal selector lists that use the HTML flag, will automatically get the `html` namespace.
+        if is_html:
+            namespaces = self.namespaces
+            iframe_restrict = self.iframe_restrict
+            self.namespaces = {'html': NS_XHTML}
+            self.iframe_restrict = True
+
+        if not is_html or self.is_html:
+            for selector in selectors:
+                match = is_not
+                # We have a un-matchable situation (like `:focus` as you can focus an element in this environment)
+                if isinstance(selector, ct.SelectorNull):
+                    continue
+                # Verify tag matches
+                if not self.match_tag(el, selector.tag):
+                    continue
+                # Verify tag is defined
+                if selector.flags & ct.SEL_DEFINED and not self.match_defined(el):
+                    continue
+                # Verify element is root
+                if selector.flags & ct.SEL_ROOT and not self.match_root(el):
+                    continue
+                # Verify element is scope
+                if selector.flags & ct.SEL_SCOPE and not self.match_scope(el):
+                    continue
+                # Verify element has placeholder shown
+                if selector.flags & ct.SEL_PLACEHOLDER_SHOWN and not self.match_placeholder_shown(el):
+                    continue
+                # Verify `nth` matches
+                if not self.match_nth(el, selector.nth):
+                    continue
+                if selector.flags & ct.SEL_EMPTY and not self.match_empty(el):
+                    continue
+                # Verify id matches
+                if selector.ids and not self.match_id(el, selector.ids):
+                    continue
+                # Verify classes match
+                if selector.classes and not self.match_classes(el, selector.classes):
+                    continue
+                # Verify attribute(s) match
+                if not self.match_attributes(el, selector.attributes):
+                    continue
+                # Verify ranges
+                if selector.flags & RANGES and not self.match_range(el, selector.flags & RANGES):
+                    continue
+                # Verify language patterns
+                if selector.lang and not self.match_lang(el, selector.lang):
+                    continue
+                # Verify pseudo selector patterns
+                if selector.selectors and not self.match_subselectors(el, selector.selectors):
+                    continue
+                # Verify relationship selectors
+                if selector.relation and not self.match_relations(el, selector.relation):
+                    continue
+                # Validate that the current default selector match corresponds to the first submit button in the form
+                if selector.flags & ct.SEL_DEFAULT and not self.match_default(el):
+                    continue
+                # Validate that the unset radio button is among radio buttons with the same name in a form that are
+                # also not set.
+                if selector.flags & ct.SEL_INDETERMINATE and not self.match_indeterminate(el):
+                    continue
+                # Validate element directionality
+                if selector.flags & DIR_FLAGS and not self.match_dir(el, selector.flags & DIR_FLAGS):
+                    continue
+                # Validate that the tag contains the specified text.
+                if not self.match_contains(el, selector.contains):
+                    continue
+                match = not is_not
+                break
+
+        # Restore actual namespaces being used for external selector lists
+        if is_html:
+            self.namespaces = namespaces
+            self.iframe_restrict = iframe_restrict
+
+        return match
+
+    def select(self, limit=0):
+        """Match all tags under the targeted tag."""
+
+        if limit < 1:
+            limit = None
+
+        for child in self.get_descendants(self.tag):
+            if self.match(child):
+                yield child
+                if limit is not None:
+                    limit -= 1
+                    if limit < 1:
+                        break
+
+    def closest(self):
+        """Match closest ancestor."""
+
+        current = self.tag
+        closest = None
+        while closest is None and current is not None:
+            if self.match(current):
+                closest = current
+            else:
+                current = self.get_parent(current)
+        return closest
+
+    def filter(self):  # noqa A001
+        """Filter tag's children."""
+
+        return [tag for tag in self.get_contents(self.tag) if not self.is_navigable_string(tag) and self.match(tag)]
+
+    def match(self, el):
+        """Match."""
+
+        return not self.is_doc(el) and self.is_tag(el) and self.match_selectors(el, self.selectors)
+
+
+class CSSMatch(_DocumentNav, _Match):
+    """The Beautiful Soup CSS match class."""
+
+
+class SoupSieve(ct.Immutable):
+    """Compiled Soup Sieve selector matching object."""
+
+    __slots__ = ("pattern", "selectors", "namespaces", "custom", "flags", "_hash")
+
+    def __init__(self, pattern, selectors, namespaces, custom, flags):
+        """Initialize."""
+
+        super(SoupSieve, self).__init__(
+            pattern=pattern,
+            selectors=selectors,
+            namespaces=namespaces,
+            custom=custom,
+            flags=flags
+        )
+
+    def match(self, tag):
+        """Match."""
+
+        return CSSMatch(self.selectors, tag, self.namespaces, self.flags).match(tag)
+
+    def closest(self, tag):
+        """Match closest ancestor."""
+
+        return CSSMatch(self.selectors, tag, self.namespaces, self.flags).closest()
+
+    def filter(self, iterable):  # noqa A001
+        """
+        Filter.
+
+        `CSSMatch` can cache certain searches for tags of the same document,
+        so if we are given a tag, all tags are from the same document,
+        and we can take advantage of the optimization.
+
+        Any other kind of iterable could have tags from different documents or detached tags,
+        so for those, we use a new `CSSMatch` for each item in the iterable.
+        """
+
+        if CSSMatch.is_tag(iterable):
+            return CSSMatch(self.selectors, iterable, self.namespaces, self.flags).filter()
+        else:
+            return [node for node in iterable if not CSSMatch.is_navigable_string(node) and self.match(node)]
+
+    def select_one(self, tag):
+        """Select a single tag."""
+
+        tags = self.select(tag, limit=1)
+        return tags[0] if tags else None
+
+    def select(self, tag, limit=0):
+        """Select the specified tags."""
+
+        return list(self.iselect(tag, limit))
+
+    def iselect(self, tag, limit=0):
+        """Iterate the specified tags."""
+
+        for el in CSSMatch(self.selectors, tag, self.namespaces, self.flags).select(limit):
+            yield el
+
+    def __repr__(self):  # pragma: no cover
+        """Representation."""
+
+        return "SoupSieve(pattern={!r}, namespaces={!r}, custom={!r}, flags={!r})".format(
+            self.pattern,
+            self.namespaces,
+            self.custom,
+            self.flags
+        )
+
+    __str__ = __repr__
+
+
+ct.pickle_register(SoupSieve)