--- a/env/lib/python3.7/site-packages/requests/utils.py	Thu May 14 16:47:39 2020 -0400
+++ /dev/null	Thu Jan 01 00:00:00 1970 +0000
@@ -1,982 +0,0 @@
-# -*- coding: utf-8 -*-
-
-"""
-requests.utils
-~~~~~~~~~~~~~~
-
-This module provides utility functions that are used within Requests
-that are also useful for external consumption.
-"""
-
-import codecs
-import contextlib
-import io
-import os
-import re
-import socket
-import struct
-import sys
-import tempfile
-import warnings
-import zipfile
-from collections import OrderedDict
-
-from .__version__ import __version__
-from . import certs
-# to_native_string is unused here, but imported here for backwards compatibility
-from ._internal_utils import to_native_string
-from .compat import parse_http_list as _parse_list_header
-from .compat import (
-    quote, urlparse, bytes, str, unquote, getproxies,
-    proxy_bypass, urlunparse, basestring, integer_types, is_py3,
-    proxy_bypass_environment, getproxies_environment, Mapping)
-from .cookies import cookiejar_from_dict
-from .structures import CaseInsensitiveDict
-from .exceptions import (
-    InvalidURL, InvalidHeader, FileModeWarning, UnrewindableBodyError)
-
-NETRC_FILES = ('.netrc', '_netrc')
-
-DEFAULT_CA_BUNDLE_PATH = certs.where()
-
-DEFAULT_PORTS = {'http': 80, 'https': 443}
-
-
-if sys.platform == 'win32':
-    # provide a proxy_bypass version on Windows without DNS lookups
-
-    def proxy_bypass_registry(host):
-        try:
-            if is_py3:
-                import winreg
-            else:
-                import _winreg as winreg
-        except ImportError:
-            return False
-
-        try:
-            internetSettings = winreg.OpenKey(winreg.HKEY_CURRENT_USER,
-                r'Software\Microsoft\Windows\CurrentVersion\Internet Settings')
-            # ProxyEnable could be REG_SZ or REG_DWORD, normalizing it
-            proxyEnable = int(winreg.QueryValueEx(internetSettings,
-                                              'ProxyEnable')[0])
-            # ProxyOverride is almost always a string
-            proxyOverride = winreg.QueryValueEx(internetSettings,
-                                                'ProxyOverride')[0]
-        except OSError:
-            return False
-        if not proxyEnable or not proxyOverride:
-            return False
-
-        # make a check value list from the registry entry: replace the
-        # '<local>' string by the localhost entry and the corresponding
-        # canonical entry.
-        proxyOverride = proxyOverride.split(';')
-        # now check if we match one of the registry values.
-        for test in proxyOverride:
-            if test == '<local>':
-                if '.' not in host:
-                    return True
-            test = test.replace(".", r"\.")     # mask dots
-            test = test.replace("*", r".*")     # change glob sequence
-            test = test.replace("?", r".")      # change glob char
-            if re.match(test, host, re.I):
-                return True
-        return False
-
-    def proxy_bypass(host):  # noqa
-        """Return True, if the host should be bypassed.
-
-        Checks proxy settings gathered from the environment, if specified,
-        or the registry.
-        """
-        if getproxies_environment():
-            return proxy_bypass_environment(host)
-        else:
-            return proxy_bypass_registry(host)
-
-
-def dict_to_sequence(d):
-    """Returns an internal sequence dictionary update."""
-
-    if hasattr(d, 'items'):
-        d = d.items()
-
-    return d
-
-
-def super_len(o):
-    total_length = None
-    current_position = 0
-
-    if hasattr(o, '__len__'):
-        total_length = len(o)
-
-    elif hasattr(o, 'len'):
-        total_length = o.len
-
-    elif hasattr(o, 'fileno'):
-        try:
-            fileno = o.fileno()
-        except io.UnsupportedOperation:
-            pass
-        else:
-            total_length = os.fstat(fileno).st_size
-
-            # Having used fstat to determine the file length, we need to
-            # confirm that this file was opened up in binary mode.
-            if 'b' not in o.mode:
-                warnings.warn((
-                    "Requests has determined the content-length for this "
-                    "request using the binary size of the file: however, the "
-                    "file has been opened in text mode (i.e. without the 'b' "
-                    "flag in the mode). This may lead to an incorrect "
-                    "content-length. In Requests 3.0, support will be removed "
-                    "for files in text mode."),
-                    FileModeWarning
-                )
-
-    if hasattr(o, 'tell'):
-        try:
-            current_position = o.tell()
-        except (OSError, IOError):
-            # This can happen in some weird situations, such as when the file
-            # is actually a special file descriptor like stdin. In this
-            # instance, we don't know what the length is, so set it to zero and
-            # let requests chunk it instead.
-            if total_length is not None:
-                current_position = total_length
-        else:
-            if hasattr(o, 'seek') and total_length is None:
-                # StringIO and BytesIO have seek but no useable fileno
-                try:
-                    # seek to end of file
-                    o.seek(0, 2)
-                    total_length = o.tell()
-
-                    # seek back to current position to support
-                    # partially read file-like objects
-                    o.seek(current_position or 0)
-                except (OSError, IOError):
-                    total_length = 0
-
-    if total_length is None:
-        total_length = 0
-
-    return max(0, total_length - current_position)
-
-
-def get_netrc_auth(url, raise_errors=False):
-    """Returns the Requests tuple auth for a given url from netrc."""
-
-    try:
-        from netrc import netrc, NetrcParseError
-
-        netrc_path = None
-
-        for f in NETRC_FILES:
-            try:
-                loc = os.path.expanduser('~/{}'.format(f))
-            except KeyError:
-                # os.path.expanduser can fail when $HOME is undefined and
-                # getpwuid fails. See https://bugs.python.org/issue20164 &
-                # https://github.com/psf/requests/issues/1846
-                return
-
-            if os.path.exists(loc):
-                netrc_path = loc
-                break
-
-        # Abort early if there isn't one.
-        if netrc_path is None:
-            return
-
-        ri = urlparse(url)
-
-        # Strip port numbers from netloc. This weird `if...encode`` dance is
-        # used for Python 3.2, which doesn't support unicode literals.
-        splitstr = b':'
-        if isinstance(url, str):
-            splitstr = splitstr.decode('ascii')
-        host = ri.netloc.split(splitstr)[0]
-
-        try:
-            _netrc = netrc(netrc_path).authenticators(host)
-            if _netrc:
-                # Return with login / password
-                login_i = (0 if _netrc[0] else 1)
-                return (_netrc[login_i], _netrc[2])
-        except (NetrcParseError, IOError):
-            # If there was a parsing error or a permissions issue reading the file,
-            # we'll just skip netrc auth unless explicitly asked to raise errors.
-            if raise_errors:
-                raise
-
-    # AppEngine hackiness.
-    except (ImportError, AttributeError):
-        pass
-
-
-def guess_filename(obj):
-    """Tries to guess the filename of the given object."""
-    name = getattr(obj, 'name', None)
-    if (name and isinstance(name, basestring) and name[0] != '<' and
-            name[-1] != '>'):
-        return os.path.basename(name)
-
-
-def extract_zipped_paths(path):
-    """Replace nonexistent paths that look like they refer to a member of a zip
-    archive with the location of an extracted copy of the target, or else
-    just return the provided path unchanged.
-    """
-    if os.path.exists(path):
-        # this is already a valid path, no need to do anything further
-        return path
-
-    # find the first valid part of the provided path and treat that as a zip archive
-    # assume the rest of the path is the name of a member in the archive
-    archive, member = os.path.split(path)
-    while archive and not os.path.exists(archive):
-        archive, prefix = os.path.split(archive)
-        member = '/'.join([prefix, member])
-
-    if not zipfile.is_zipfile(archive):
-        return path
-
-    zip_file = zipfile.ZipFile(archive)
-    if member not in zip_file.namelist():
-        return path
-
-    # we have a valid zip archive and a valid member of that archive
-    tmp = tempfile.gettempdir()
-    extracted_path = os.path.join(tmp, *member.split('/'))
-    if not os.path.exists(extracted_path):
-        extracted_path = zip_file.extract(member, path=tmp)
-
-    return extracted_path
-
-
-def from_key_val_list(value):
-    """Take an object and test to see if it can be represented as a
-    dictionary. Unless it can not be represented as such, return an
-    OrderedDict, e.g.,
-
-    ::
-
-        >>> from_key_val_list([('key', 'val')])
-        OrderedDict([('key', 'val')])
-        >>> from_key_val_list('string')
-        Traceback (most recent call last):
-        ...
-        ValueError: cannot encode objects that are not 2-tuples
-        >>> from_key_val_list({'key': 'val'})
-        OrderedDict([('key', 'val')])
-
-    :rtype: OrderedDict
-    """
-    if value is None:
-        return None
-
-    if isinstance(value, (str, bytes, bool, int)):
-        raise ValueError('cannot encode objects that are not 2-tuples')
-
-    return OrderedDict(value)
-
-
-def to_key_val_list(value):
-    """Take an object and test to see if it can be represented as a
-    dictionary. If it can be, return a list of tuples, e.g.,
-
-    ::
-
-        >>> to_key_val_list([('key', 'val')])
-        [('key', 'val')]
-        >>> to_key_val_list({'key': 'val'})
-        [('key', 'val')]
-        >>> to_key_val_list('string')
-        Traceback (most recent call last):
-        ...
-        ValueError: cannot encode objects that are not 2-tuples
-
-    :rtype: list
-    """
-    if value is None:
-        return None
-
-    if isinstance(value, (str, bytes, bool, int)):
-        raise ValueError('cannot encode objects that are not 2-tuples')
-
-    if isinstance(value, Mapping):
-        value = value.items()
-
-    return list(value)
-
-
-# From mitsuhiko/werkzeug (used with permission).
-def parse_list_header(value):
-    """Parse lists as described by RFC 2068 Section 2.
-
-    In particular, parse comma-separated lists where the elements of
-    the list may include quoted-strings.  A quoted-string could
-    contain a comma.  A non-quoted string could have quotes in the
-    middle.  Quotes are removed automatically after parsing.
-
-    It basically works like :func:`parse_set_header` just that items
-    may appear multiple times and case sensitivity is preserved.
-
-    The return value is a standard :class:`list`:
-
-    >>> parse_list_header('token, "quoted value"')
-    ['token', 'quoted value']
-
-    To create a header from the :class:`list` again, use the
-    :func:`dump_header` function.
-
-    :param value: a string with a list header.
-    :return: :class:`list`
-    :rtype: list
-    """
-    result = []
-    for item in _parse_list_header(value):
-        if item[:1] == item[-1:] == '"':
-            item = unquote_header_value(item[1:-1])
-        result.append(item)
-    return result
-
-
-# From mitsuhiko/werkzeug (used with permission).
-def parse_dict_header(value):
-    """Parse lists of key, value pairs as described by RFC 2068 Section 2 and
-    convert them into a python dict:
-
-    >>> d = parse_dict_header('foo="is a fish", bar="as well"')
-    >>> type(d) is dict
-    True
-    >>> sorted(d.items())
-    [('bar', 'as well'), ('foo', 'is a fish')]
-
-    If there is no value for a key it will be `None`:
-
-    >>> parse_dict_header('key_without_value')
-    {'key_without_value': None}
-
-    To create a header from the :class:`dict` again, use the
-    :func:`dump_header` function.
-
-    :param value: a string with a dict header.
-    :return: :class:`dict`
-    :rtype: dict
-    """
-    result = {}
-    for item in _parse_list_header(value):
-        if '=' not in item:
-            result[item] = None
-            continue
-        name, value = item.split('=', 1)
-        if value[:1] == value[-1:] == '"':
-            value = unquote_header_value(value[1:-1])
-        result[name] = value
-    return result
-
-
-# From mitsuhiko/werkzeug (used with permission).
-def unquote_header_value(value, is_filename=False):
-    r"""Unquotes a header value.  (Reversal of :func:`quote_header_value`).
-    This does not use the real unquoting but what browsers are actually
-    using for quoting.
-
-    :param value: the header value to unquote.
-    :rtype: str
-    """
-    if value and value[0] == value[-1] == '"':
-        # this is not the real unquoting, but fixing this so that the
-        # RFC is met will result in bugs with internet explorer and
-        # probably some other browsers as well.  IE for example is
-        # uploading files with "C:\foo\bar.txt" as filename
-        value = value[1:-1]
-
-        # if this is a filename and the starting characters look like
-        # a UNC path, then just return the value without quotes.  Using the
-        # replace sequence below on a UNC path has the effect of turning
-        # the leading double slash into a single slash and then
-        # _fix_ie_filename() doesn't work correctly.  See #458.
-        if not is_filename or value[:2] != '\\\\':
-            return value.replace('\\\\', '\\').replace('\\"', '"')
-    return value
-
-
-def dict_from_cookiejar(cj):
-    """Returns a key/value dictionary from a CookieJar.
-
-    :param cj: CookieJar object to extract cookies from.
-    :rtype: dict
-    """
-
-    cookie_dict = {}
-
-    for cookie in cj:
-        cookie_dict[cookie.name] = cookie.value
-
-    return cookie_dict
-
-
-def add_dict_to_cookiejar(cj, cookie_dict):
-    """Returns a CookieJar from a key/value dictionary.
-
-    :param cj: CookieJar to insert cookies into.
-    :param cookie_dict: Dict of key/values to insert into CookieJar.
-    :rtype: CookieJar
-    """
-
-    return cookiejar_from_dict(cookie_dict, cj)
-
-
-def get_encodings_from_content(content):
-    """Returns encodings from given content string.
-
-    :param content: bytestring to extract encodings from.
-    """
-    warnings.warn((
-        'In requests 3.0, get_encodings_from_content will be removed. For '
-        'more information, please see the discussion on issue #2266. (This'
-        ' warning should only appear once.)'),
-        DeprecationWarning)
-
-    charset_re = re.compile(r'<meta.*?charset=["\']*(.+?)["\'>]', flags=re.I)
-    pragma_re = re.compile(r'<meta.*?content=["\']*;?charset=(.+?)["\'>]', flags=re.I)
-    xml_re = re.compile(r'^<\?xml.*?encoding=["\']*(.+?)["\'>]')
-
-    return (charset_re.findall(content) +
-            pragma_re.findall(content) +
-            xml_re.findall(content))
-
-
-def _parse_content_type_header(header):
-    """Returns content type and parameters from given header
-
-    :param header: string
-    :return: tuple containing content type and dictionary of
-         parameters
-    """
-
-    tokens = header.split(';')
-    content_type, params = tokens[0].strip(), tokens[1:]
-    params_dict = {}
-    items_to_strip = "\"' "
-
-    for param in params:
-        param = param.strip()
-        if param:
-            key, value = param, True
-            index_of_equals = param.find("=")
-            if index_of_equals != -1:
-                key = param[:index_of_equals].strip(items_to_strip)
-                value = param[index_of_equals + 1:].strip(items_to_strip)
-            params_dict[key.lower()] = value
-    return content_type, params_dict
-
-
-def get_encoding_from_headers(headers):
-    """Returns encodings from given HTTP Header Dict.
-
-    :param headers: dictionary to extract encoding from.
-    :rtype: str
-    """
-
-    content_type = headers.get('content-type')
-
-    if not content_type:
-        return None
-
-    content_type, params = _parse_content_type_header(content_type)
-
-    if 'charset' in params:
-        return params['charset'].strip("'\"")
-
-    if 'text' in content_type:
-        return 'ISO-8859-1'
-
-
-def stream_decode_response_unicode(iterator, r):
-    """Stream decodes a iterator."""
-
-    if r.encoding is None:
-        for item in iterator:
-            yield item
-        return
-
-    decoder = codecs.getincrementaldecoder(r.encoding)(errors='replace')
-    for chunk in iterator:
-        rv = decoder.decode(chunk)
-        if rv:
-            yield rv
-    rv = decoder.decode(b'', final=True)
-    if rv:
-        yield rv
-
-
-def iter_slices(string, slice_length):
-    """Iterate over slices of a string."""
-    pos = 0
-    if slice_length is None or slice_length <= 0:
-        slice_length = len(string)
-    while pos < len(string):
-        yield string[pos:pos + slice_length]
-        pos += slice_length
-
-
-def get_unicode_from_response(r):
-    """Returns the requested content back in unicode.
-
-    :param r: Response object to get unicode content from.
-
-    Tried:
-
-    1. charset from content-type
-    2. fall back and replace all unicode characters
-
-    :rtype: str
-    """
-    warnings.warn((
-        'In requests 3.0, get_unicode_from_response will be removed. For '
-        'more information, please see the discussion on issue #2266. (This'
-        ' warning should only appear once.)'),
-        DeprecationWarning)
-
-    tried_encodings = []
-
-    # Try charset from content-type
-    encoding = get_encoding_from_headers(r.headers)
-
-    if encoding:
-        try:
-            return str(r.content, encoding)
-        except UnicodeError:
-            tried_encodings.append(encoding)
-
-    # Fall back:
-    try:
-        return str(r.content, encoding, errors='replace')
-    except TypeError:
-        return r.content
-
-
-# The unreserved URI characters (RFC 3986)
-UNRESERVED_SET = frozenset(
-    "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz" + "0123456789-._~")
-
-
-def unquote_unreserved(uri):
-    """Un-escape any percent-escape sequences in a URI that are unreserved
-    characters. This leaves all reserved, illegal and non-ASCII bytes encoded.
-
-    :rtype: str
-    """
-    parts = uri.split('%')
-    for i in range(1, len(parts)):
-        h = parts[i][0:2]
-        if len(h) == 2 and h.isalnum():
-            try:
-                c = chr(int(h, 16))
-            except ValueError:
-                raise InvalidURL("Invalid percent-escape sequence: '%s'" % h)
-
-            if c in UNRESERVED_SET:
-                parts[i] = c + parts[i][2:]
-            else:
-                parts[i] = '%' + parts[i]
-        else:
-            parts[i] = '%' + parts[i]
-    return ''.join(parts)
-
-
-def requote_uri(uri):
-    """Re-quote the given URI.
-
-    This function passes the given URI through an unquote/quote cycle to
-    ensure that it is fully and consistently quoted.
-
-    :rtype: str
-    """
-    safe_with_percent = "!#$%&'()*+,/:;=?@[]~"
-    safe_without_percent = "!#$&'()*+,/:;=?@[]~"
-    try:
-        # Unquote only the unreserved characters
-        # Then quote only illegal characters (do not quote reserved,
-        # unreserved, or '%')
-        return quote(unquote_unreserved(uri), safe=safe_with_percent)
-    except InvalidURL:
-        # We couldn't unquote the given URI, so let's try quoting it, but
-        # there may be unquoted '%'s in the URI. We need to make sure they're
-        # properly quoted so they do not cause issues elsewhere.
-        return quote(uri, safe=safe_without_percent)
-
-
-def address_in_network(ip, net):
-    """This function allows you to check if an IP belongs to a network subnet
-
-    Example: returns True if ip = 192.168.1.1 and net = 192.168.1.0/24
-             returns False if ip = 192.168.1.1 and net = 192.168.100.0/24
-
-    :rtype: bool
-    """
-    ipaddr = struct.unpack('=L', socket.inet_aton(ip))[0]
-    netaddr, bits = net.split('/')
-    netmask = struct.unpack('=L', socket.inet_aton(dotted_netmask(int(bits))))[0]
-    network = struct.unpack('=L', socket.inet_aton(netaddr))[0] & netmask
-    return (ipaddr & netmask) == (network & netmask)
-
-
-def dotted_netmask(mask):
-    """Converts mask from /xx format to xxx.xxx.xxx.xxx
-
-    Example: if mask is 24 function returns 255.255.255.0
-
-    :rtype: str
-    """
-    bits = 0xffffffff ^ (1 << 32 - mask) - 1
-    return socket.inet_ntoa(struct.pack('>I', bits))
-
-
-def is_ipv4_address(string_ip):
-    """
-    :rtype: bool
-    """
-    try:
-        socket.inet_aton(string_ip)
-    except socket.error:
-        return False
-    return True
-
-
-def is_valid_cidr(string_network):
-    """
-    Very simple check of the cidr format in no_proxy variable.
-
-    :rtype: bool
-    """
-    if string_network.count('/') == 1:
-        try:
-            mask = int(string_network.split('/')[1])
-        except ValueError:
-            return False
-
-        if mask < 1 or mask > 32:
-            return False
-
-        try:
-            socket.inet_aton(string_network.split('/')[0])
-        except socket.error:
-            return False
-    else:
-        return False
-    return True
-
-
-@contextlib.contextmanager
-def set_environ(env_name, value):
-    """Set the environment variable 'env_name' to 'value'
-
-    Save previous value, yield, and then restore the previous value stored in
-    the environment variable 'env_name'.
-
-    If 'value' is None, do nothing"""
-    value_changed = value is not None
-    if value_changed:
-        old_value = os.environ.get(env_name)
-        os.environ[env_name] = value
-    try:
-        yield
-    finally:
-        if value_changed:
-            if old_value is None:
-                del os.environ[env_name]
-            else:
-                os.environ[env_name] = old_value
-
-
-def should_bypass_proxies(url, no_proxy):
-    """
-    Returns whether we should bypass proxies or not.
-
-    :rtype: bool
-    """
-    # Prioritize lowercase environment variables over uppercase
-    # to keep a consistent behaviour with other http projects (curl, wget).
-    get_proxy = lambda k: os.environ.get(k) or os.environ.get(k.upper())
-
-    # First check whether no_proxy is defined. If it is, check that the URL
-    # we're getting isn't in the no_proxy list.
-    no_proxy_arg = no_proxy
-    if no_proxy is None:
-        no_proxy = get_proxy('no_proxy')
-    parsed = urlparse(url)
-
-    if parsed.hostname is None:
-        # URLs don't always have hostnames, e.g. file:/// urls.
-        return True
-
-    if no_proxy:
-        # We need to check whether we match here. We need to see if we match
-        # the end of the hostname, both with and without the port.
-        no_proxy = (
-            host for host in no_proxy.replace(' ', '').split(',') if host
-        )
-
-        if is_ipv4_address(parsed.hostname):
-            for proxy_ip in no_proxy:
-                if is_valid_cidr(proxy_ip):
-                    if address_in_network(parsed.hostname, proxy_ip):
-                        return True
-                elif parsed.hostname == proxy_ip:
-                    # If no_proxy ip was defined in plain IP notation instead of cidr notation &
-                    # matches the IP of the index
-                    return True
-        else:
-            host_with_port = parsed.hostname
-            if parsed.port:
-                host_with_port += ':{}'.format(parsed.port)
-
-            for host in no_proxy:
-                if parsed.hostname.endswith(host) or host_with_port.endswith(host):
-                    # The URL does match something in no_proxy, so we don't want
-                    # to apply the proxies on this URL.
-                    return True
-
-    with set_environ('no_proxy', no_proxy_arg):
-        # parsed.hostname can be `None` in cases such as a file URI.
-        try:
-            bypass = proxy_bypass(parsed.hostname)
-        except (TypeError, socket.gaierror):
-            bypass = False
-
-    if bypass:
-        return True
-
-    return False
-
-
-def get_environ_proxies(url, no_proxy=None):
-    """
-    Return a dict of environment proxies.
-
-    :rtype: dict
-    """
-    if should_bypass_proxies(url, no_proxy=no_proxy):
-        return {}
-    else:
-        return getproxies()
-
-
-def select_proxy(url, proxies):
-    """Select a proxy for the url, if applicable.
-
-    :param url: The url being for the request
-    :param proxies: A dictionary of schemes or schemes and hosts to proxy URLs
-    """
-    proxies = proxies or {}
-    urlparts = urlparse(url)
-    if urlparts.hostname is None:
-        return proxies.get(urlparts.scheme, proxies.get('all'))
-
-    proxy_keys = [
-        urlparts.scheme + '://' + urlparts.hostname,
-        urlparts.scheme,
-        'all://' + urlparts.hostname,
-        'all',
-    ]
-    proxy = None
-    for proxy_key in proxy_keys:
-        if proxy_key in proxies:
-            proxy = proxies[proxy_key]
-            break
-
-    return proxy
-
-
-def default_user_agent(name="python-requests"):
-    """
-    Return a string representing the default user agent.
-
-    :rtype: str
-    """
-    return '%s/%s' % (name, __version__)
-
-
-def default_headers():
-    """
-    :rtype: requests.structures.CaseInsensitiveDict
-    """
-    return CaseInsensitiveDict({
-        'User-Agent': default_user_agent(),
-        'Accept-Encoding': ', '.join(('gzip', 'deflate')),
-        'Accept': '*/*',
-        'Connection': 'keep-alive',
-    })
-
-
-def parse_header_links(value):
-    """Return a list of parsed link headers proxies.
-
-    i.e. Link: <http:/.../front.jpeg>; rel=front; type="image/jpeg",<http://.../back.jpeg>; rel=back;type="image/jpeg"
-
-    :rtype: list
-    """
-
-    links = []
-
-    replace_chars = ' \'"'
-
-    value = value.strip(replace_chars)
-    if not value:
-        return links
-
-    for val in re.split(', *<', value):
-        try:
-            url, params = val.split(';', 1)
-        except ValueError:
-            url, params = val, ''
-
-        link = {'url': url.strip('<> \'"')}
-
-        for param in params.split(';'):
-            try:
-                key, value = param.split('=')
-            except ValueError:
-                break
-
-            link[key.strip(replace_chars)] = value.strip(replace_chars)
-
-        links.append(link)
-
-    return links
-
-
-# Null bytes; no need to recreate these on each call to guess_json_utf
-_null = '\x00'.encode('ascii')  # encoding to ASCII for Python 3
-_null2 = _null * 2
-_null3 = _null * 3
-
-
-def guess_json_utf(data):
-    """
-    :rtype: str
-    """
-    # JSON always starts with two ASCII characters, so detection is as
-    # easy as counting the nulls and from their location and count
-    # determine the encoding. Also detect a BOM, if present.
-    sample = data[:4]
-    if sample in (codecs.BOM_UTF32_LE, codecs.BOM_UTF32_BE):
-        return 'utf-32'     # BOM included
-    if sample[:3] == codecs.BOM_UTF8:
-        return 'utf-8-sig'  # BOM included, MS style (discouraged)
-    if sample[:2] in (codecs.BOM_UTF16_LE, codecs.BOM_UTF16_BE):
-        return 'utf-16'     # BOM included
-    nullcount = sample.count(_null)
-    if nullcount == 0:
-        return 'utf-8'
-    if nullcount == 2:
-        if sample[::2] == _null2:   # 1st and 3rd are null
-            return 'utf-16-be'
-        if sample[1::2] == _null2:  # 2nd and 4th are null
-            return 'utf-16-le'
-        # Did not detect 2 valid UTF-16 ascii-range characters
-    if nullcount == 3:
-        if sample[:3] == _null3:
-            return 'utf-32-be'
-        if sample[1:] == _null3:
-            return 'utf-32-le'
-        # Did not detect a valid UTF-32 ascii-range character
-    return None
-
-
-def prepend_scheme_if_needed(url, new_scheme):
-    """Given a URL that may or may not have a scheme, prepend the given scheme.
-    Does not replace a present scheme with the one provided as an argument.
-
-    :rtype: str
-    """
-    scheme, netloc, path, params, query, fragment = urlparse(url, new_scheme)
-
-    # urlparse is a finicky beast, and sometimes decides that there isn't a
-    # netloc present. Assume that it's being over-cautious, and switch netloc
-    # and path if urlparse decided there was no netloc.
-    if not netloc:
-        netloc, path = path, netloc
-
-    return urlunparse((scheme, netloc, path, params, query, fragment))
-
-
-def get_auth_from_url(url):
-    """Given a url with authentication components, extract them into a tuple of
-    username,password.
-
-    :rtype: (str,str)
-    """
-    parsed = urlparse(url)
-
-    try:
-        auth = (unquote(parsed.username), unquote(parsed.password))
-    except (AttributeError, TypeError):
-        auth = ('', '')
-
-    return auth
-
-
-# Moved outside of function to avoid recompile every call
-_CLEAN_HEADER_REGEX_BYTE = re.compile(b'^\\S[^\\r\\n]*$|^$')
-_CLEAN_HEADER_REGEX_STR = re.compile(r'^\S[^\r\n]*$|^$')
-
-
-def check_header_validity(header):
-    """Verifies that header value is a string which doesn't contain
-    leading whitespace or return characters. This prevents unintended
-    header injection.
-
-    :param header: tuple, in the format (name, value).
-    """
-    name, value = header
-
-    if isinstance(value, bytes):
-        pat = _CLEAN_HEADER_REGEX_BYTE
-    else:
-        pat = _CLEAN_HEADER_REGEX_STR
-    try:
-        if not pat.match(value):
-            raise InvalidHeader("Invalid return character or leading space in header: %s" % name)
-    except TypeError:
-        raise InvalidHeader("Value for header {%s: %s} must be of type str or "
-                            "bytes, not %s" % (name, value, type(value)))
-
-
-def urldefragauth(url):
-    """
-    Given a url remove the fragment and the authentication part.
-
-    :rtype: str
-    """
-    scheme, netloc, path, params, query, fragment = urlparse(url)
-
-    # see func:`prepend_scheme_if_needed`
-    if not netloc:
-        netloc, path = path, netloc
-
-    netloc = netloc.rsplit('@', 1)[-1]
-
-    return urlunparse((scheme, netloc, path, params, query, ''))
-
-
-def rewind_body(prepared_request):
-    """Move file pointer back to its recorded starting position
-    so it can be read again on redirect.
-    """
-    body_seek = getattr(prepared_request.body, 'seek', None)
-    if body_seek is not None and isinstance(prepared_request._body_position, integer_types):
-        try:
-            body_seek(prepared_request._body_position)
-        except (IOError, OSError):
-            raise UnrewindableBodyError("An error occurred when rewinding request "
-                                        "body for redirect.")
-    else:
-        raise UnrewindableBodyError("Unable to rewind request body for redirect.")