--- a/env/lib/python3.7/site-packages/jinja2/runtime.py	Thu May 14 16:47:39 2020 -0400
+++ /dev/null	Thu Jan 01 00:00:00 1970 +0000
@@ -1,1011 +0,0 @@
-# -*- coding: utf-8 -*-
-"""The runtime functions and state used by compiled templates."""
-import sys
-from itertools import chain
-from types import MethodType
-
-from markupsafe import escape  # noqa: F401
-from markupsafe import Markup
-from markupsafe import soft_unicode
-
-from ._compat import abc
-from ._compat import imap
-from ._compat import implements_iterator
-from ._compat import implements_to_string
-from ._compat import iteritems
-from ._compat import PY2
-from ._compat import string_types
-from ._compat import text_type
-from ._compat import with_metaclass
-from .exceptions import TemplateNotFound  # noqa: F401
-from .exceptions import TemplateRuntimeError  # noqa: F401
-from .exceptions import UndefinedError
-from .nodes import EvalContext
-from .utils import concat
-from .utils import evalcontextfunction
-from .utils import internalcode
-from .utils import missing
-from .utils import Namespace  # noqa: F401
-from .utils import object_type_repr
-
-# these variables are exported to the template runtime
-exported = [
-    "LoopContext",
-    "TemplateReference",
-    "Macro",
-    "Markup",
-    "TemplateRuntimeError",
-    "missing",
-    "concat",
-    "escape",
-    "markup_join",
-    "unicode_join",
-    "to_string",
-    "identity",
-    "TemplateNotFound",
-    "Namespace",
-    "Undefined",
-]
-
-#: the name of the function that is used to convert something into
-#: a string.  We can just use the text type here.
-to_string = text_type
-
-
-def identity(x):
-    """Returns its argument. Useful for certain things in the
-    environment.
-    """
-    return x
-
-
-def markup_join(seq):
-    """Concatenation that escapes if necessary and converts to unicode."""
-    buf = []
-    iterator = imap(soft_unicode, seq)
-    for arg in iterator:
-        buf.append(arg)
-        if hasattr(arg, "__html__"):
-            return Markup(u"").join(chain(buf, iterator))
-    return concat(buf)
-
-
-def unicode_join(seq):
-    """Simple args to unicode conversion and concatenation."""
-    return concat(imap(text_type, seq))
-
-
-def new_context(
-    environment,
-    template_name,
-    blocks,
-    vars=None,
-    shared=None,
-    globals=None,
-    locals=None,
-):
-    """Internal helper for context creation."""
-    if vars is None:
-        vars = {}
-    if shared:
-        parent = vars
-    else:
-        parent = dict(globals or (), **vars)
-    if locals:
-        # if the parent is shared a copy should be created because
-        # we don't want to modify the dict passed
-        if shared:
-            parent = dict(parent)
-        for key, value in iteritems(locals):
-            if value is not missing:
-                parent[key] = value
-    return environment.context_class(environment, parent, template_name, blocks)
-
-
-class TemplateReference(object):
-    """The `self` in templates."""
-
-    def __init__(self, context):
-        self.__context = context
-
-    def __getitem__(self, name):
-        blocks = self.__context.blocks[name]
-        return BlockReference(name, self.__context, blocks, 0)
-
-    def __repr__(self):
-        return "<%s %r>" % (self.__class__.__name__, self.__context.name)
-
-
-def _get_func(x):
-    return getattr(x, "__func__", x)
-
-
-class ContextMeta(type):
-    def __new__(mcs, name, bases, d):
-        rv = type.__new__(mcs, name, bases, d)
-        if bases == ():
-            return rv
-
-        resolve = _get_func(rv.resolve)
-        default_resolve = _get_func(Context.resolve)
-        resolve_or_missing = _get_func(rv.resolve_or_missing)
-        default_resolve_or_missing = _get_func(Context.resolve_or_missing)
-
-        # If we have a changed resolve but no changed default or missing
-        # resolve we invert the call logic.
-        if (
-            resolve is not default_resolve
-            and resolve_or_missing is default_resolve_or_missing
-        ):
-            rv._legacy_resolve_mode = True
-        elif (
-            resolve is default_resolve
-            and resolve_or_missing is default_resolve_or_missing
-        ):
-            rv._fast_resolve_mode = True
-
-        return rv
-
-
-def resolve_or_missing(context, key, missing=missing):
-    if key in context.vars:
-        return context.vars[key]
-    if key in context.parent:
-        return context.parent[key]
-    return missing
-
-
-class Context(with_metaclass(ContextMeta)):
-    """The template context holds the variables of a template.  It stores the
-    values passed to the template and also the names the template exports.
-    Creating instances is neither supported nor useful as it's created
-    automatically at various stages of the template evaluation and should not
-    be created by hand.
-
-    The context is immutable.  Modifications on :attr:`parent` **must not**
-    happen and modifications on :attr:`vars` are allowed from generated
-    template code only.  Template filters and global functions marked as
-    :func:`contextfunction`\\s get the active context passed as first argument
-    and are allowed to access the context read-only.
-
-    The template context supports read only dict operations (`get`,
-    `keys`, `values`, `items`, `iterkeys`, `itervalues`, `iteritems`,
-    `__getitem__`, `__contains__`).  Additionally there is a :meth:`resolve`
-    method that doesn't fail with a `KeyError` but returns an
-    :class:`Undefined` object for missing variables.
-    """
-
-    # XXX: we want to eventually make this be a deprecation warning and
-    # remove it.
-    _legacy_resolve_mode = False
-    _fast_resolve_mode = False
-
-    def __init__(self, environment, parent, name, blocks):
-        self.parent = parent
-        self.vars = {}
-        self.environment = environment
-        self.eval_ctx = EvalContext(self.environment, name)
-        self.exported_vars = set()
-        self.name = name
-
-        # create the initial mapping of blocks.  Whenever template inheritance
-        # takes place the runtime will update this mapping with the new blocks
-        # from the template.
-        self.blocks = dict((k, [v]) for k, v in iteritems(blocks))
-
-        # In case we detect the fast resolve mode we can set up an alias
-        # here that bypasses the legacy code logic.
-        if self._fast_resolve_mode:
-            self.resolve_or_missing = MethodType(resolve_or_missing, self)
-
-    def super(self, name, current):
-        """Render a parent block."""
-        try:
-            blocks = self.blocks[name]
-            index = blocks.index(current) + 1
-            blocks[index]
-        except LookupError:
-            return self.environment.undefined(
-                "there is no parent block called %r." % name, name="super"
-            )
-        return BlockReference(name, self, blocks, index)
-
-    def get(self, key, default=None):
-        """Returns an item from the template context, if it doesn't exist
-        `default` is returned.
-        """
-        try:
-            return self[key]
-        except KeyError:
-            return default
-
-    def resolve(self, key):
-        """Looks up a variable like `__getitem__` or `get` but returns an
-        :class:`Undefined` object with the name of the name looked up.
-        """
-        if self._legacy_resolve_mode:
-            rv = resolve_or_missing(self, key)
-        else:
-            rv = self.resolve_or_missing(key)
-        if rv is missing:
-            return self.environment.undefined(name=key)
-        return rv
-
-    def resolve_or_missing(self, key):
-        """Resolves a variable like :meth:`resolve` but returns the
-        special `missing` value if it cannot be found.
-        """
-        if self._legacy_resolve_mode:
-            rv = self.resolve(key)
-            if isinstance(rv, Undefined):
-                rv = missing
-            return rv
-        return resolve_or_missing(self, key)
-
-    def get_exported(self):
-        """Get a new dict with the exported variables."""
-        return dict((k, self.vars[k]) for k in self.exported_vars)
-
-    def get_all(self):
-        """Return the complete context as dict including the exported
-        variables.  For optimizations reasons this might not return an
-        actual copy so be careful with using it.
-        """
-        if not self.vars:
-            return self.parent
-        if not self.parent:
-            return self.vars
-        return dict(self.parent, **self.vars)
-
-    @internalcode
-    def call(__self, __obj, *args, **kwargs):  # noqa: B902
-        """Call the callable with the arguments and keyword arguments
-        provided but inject the active context or environment as first
-        argument if the callable is a :func:`contextfunction` or
-        :func:`environmentfunction`.
-        """
-        if __debug__:
-            __traceback_hide__ = True  # noqa
-
-        # Allow callable classes to take a context
-        if hasattr(__obj, "__call__"):  # noqa: B004
-            fn = __obj.__call__
-            for fn_type in (
-                "contextfunction",
-                "evalcontextfunction",
-                "environmentfunction",
-            ):
-                if hasattr(fn, fn_type):
-                    __obj = fn
-                    break
-
-        if callable(__obj):
-            if getattr(__obj, "contextfunction", False) is True:
-                args = (__self,) + args
-            elif getattr(__obj, "evalcontextfunction", False) is True:
-                args = (__self.eval_ctx,) + args
-            elif getattr(__obj, "environmentfunction", False) is True:
-                args = (__self.environment,) + args
-        try:
-            return __obj(*args, **kwargs)
-        except StopIteration:
-            return __self.environment.undefined(
-                "value was undefined because "
-                "a callable raised a "
-                "StopIteration exception"
-            )
-
-    def derived(self, locals=None):
-        """Internal helper function to create a derived context.  This is
-        used in situations where the system needs a new context in the same
-        template that is independent.
-        """
-        context = new_context(
-            self.environment, self.name, {}, self.get_all(), True, None, locals
-        )
-        context.eval_ctx = self.eval_ctx
-        context.blocks.update((k, list(v)) for k, v in iteritems(self.blocks))
-        return context
-
-    def _all(meth):  # noqa: B902
-        def proxy(self):
-            return getattr(self.get_all(), meth)()
-
-        proxy.__doc__ = getattr(dict, meth).__doc__
-        proxy.__name__ = meth
-        return proxy
-
-    keys = _all("keys")
-    values = _all("values")
-    items = _all("items")
-
-    # not available on python 3
-    if PY2:
-        iterkeys = _all("iterkeys")
-        itervalues = _all("itervalues")
-        iteritems = _all("iteritems")
-    del _all
-
-    def __contains__(self, name):
-        return name in self.vars or name in self.parent
-
-    def __getitem__(self, key):
-        """Lookup a variable or raise `KeyError` if the variable is
-        undefined.
-        """
-        item = self.resolve_or_missing(key)
-        if item is missing:
-            raise KeyError(key)
-        return item
-
-    def __repr__(self):
-        return "<%s %s of %r>" % (
-            self.__class__.__name__,
-            repr(self.get_all()),
-            self.name,
-        )
-
-
-abc.Mapping.register(Context)
-
-
-class BlockReference(object):
-    """One block on a template reference."""
-
-    def __init__(self, name, context, stack, depth):
-        self.name = name
-        self._context = context
-        self._stack = stack
-        self._depth = depth
-
-    @property
-    def super(self):
-        """Super the block."""
-        if self._depth + 1 >= len(self._stack):
-            return self._context.environment.undefined(
-                "there is no parent block called %r." % self.name, name="super"
-            )
-        return BlockReference(self.name, self._context, self._stack, self._depth + 1)
-
-    @internalcode
-    def __call__(self):
-        rv = concat(self._stack[self._depth](self._context))
-        if self._context.eval_ctx.autoescape:
-            rv = Markup(rv)
-        return rv
-
-
-@implements_iterator
-class LoopContext:
-    """A wrapper iterable for dynamic ``for`` loops, with information
-    about the loop and iteration.
-    """
-
-    #: Current iteration of the loop, starting at 0.
-    index0 = -1
-
-    _length = None
-    _after = missing
-    _current = missing
-    _before = missing
-    _last_changed_value = missing
-
-    def __init__(self, iterable, undefined, recurse=None, depth0=0):
-        """
-        :param iterable: Iterable to wrap.
-        :param undefined: :class:`Undefined` class to use for next and
-            previous items.
-        :param recurse: The function to render the loop body when the
-            loop is marked recursive.
-        :param depth0: Incremented when looping recursively.
-        """
-        self._iterable = iterable
-        self._iterator = self._to_iterator(iterable)
-        self._undefined = undefined
-        self._recurse = recurse
-        #: How many levels deep a recursive loop currently is, starting at 0.
-        self.depth0 = depth0
-
-    @staticmethod
-    def _to_iterator(iterable):
-        return iter(iterable)
-
-    @property
-    def length(self):
-        """Length of the iterable.
-
-        If the iterable is a generator or otherwise does not have a
-        size, it is eagerly evaluated to get a size.
-        """
-        if self._length is not None:
-            return self._length
-
-        try:
-            self._length = len(self._iterable)
-        except TypeError:
-            iterable = list(self._iterator)
-            self._iterator = self._to_iterator(iterable)
-            self._length = len(iterable) + self.index + (self._after is not missing)
-
-        return self._length
-
-    def __len__(self):
-        return self.length
-
-    @property
-    def depth(self):
-        """How many levels deep a recursive loop currently is, starting at 1."""
-        return self.depth0 + 1
-
-    @property
-    def index(self):
-        """Current iteration of the loop, starting at 1."""
-        return self.index0 + 1
-
-    @property
-    def revindex0(self):
-        """Number of iterations from the end of the loop, ending at 0.
-
-        Requires calculating :attr:`length`.
-        """
-        return self.length - self.index
-
-    @property
-    def revindex(self):
-        """Number of iterations from the end of the loop, ending at 1.
-
-        Requires calculating :attr:`length`.
-        """
-        return self.length - self.index0
-
-    @property
-    def first(self):
-        """Whether this is the first iteration of the loop."""
-        return self.index0 == 0
-
-    def _peek_next(self):
-        """Return the next element in the iterable, or :data:`missing`
-        if the iterable is exhausted. Only peeks one item ahead, caching
-        the result in :attr:`_last` for use in subsequent checks. The
-        cache is reset when :meth:`__next__` is called.
-        """
-        if self._after is not missing:
-            return self._after
-
-        self._after = next(self._iterator, missing)
-        return self._after
-
-    @property
-    def last(self):
-        """Whether this is the last iteration of the loop.
-
-        Causes the iterable to advance early. See
-        :func:`itertools.groupby` for issues this can cause.
-        The :func:`groupby` filter avoids that issue.
-        """
-        return self._peek_next() is missing
-
-    @property
-    def previtem(self):
-        """The item in the previous iteration. Undefined during the
-        first iteration.
-        """
-        if self.first:
-            return self._undefined("there is no previous item")
-
-        return self._before
-
-    @property
-    def nextitem(self):
-        """The item in the next iteration. Undefined during the last
-        iteration.
-
-        Causes the iterable to advance early. See
-        :func:`itertools.groupby` for issues this can cause.
-        The :func:`groupby` filter avoids that issue.
-        """
-        rv = self._peek_next()
-
-        if rv is missing:
-            return self._undefined("there is no next item")
-
-        return rv
-
-    def cycle(self, *args):
-        """Return a value from the given args, cycling through based on
-        the current :attr:`index0`.
-
-        :param args: One or more values to cycle through.
-        """
-        if not args:
-            raise TypeError("no items for cycling given")
-
-        return args[self.index0 % len(args)]
-
-    def changed(self, *value):
-        """Return ``True`` if previously called with a different value
-        (including when called for the first time).
-
-        :param value: One or more values to compare to the last call.
-        """
-        if self._last_changed_value != value:
-            self._last_changed_value = value
-            return True
-
-        return False
-
-    def __iter__(self):
-        return self
-
-    def __next__(self):
-        if self._after is not missing:
-            rv = self._after
-            self._after = missing
-        else:
-            rv = next(self._iterator)
-
-        self.index0 += 1
-        self._before = self._current
-        self._current = rv
-        return rv, self
-
-    @internalcode
-    def __call__(self, iterable):
-        """When iterating over nested data, render the body of the loop
-        recursively with the given inner iterable data.
-
-        The loop must have the ``recursive`` marker for this to work.
-        """
-        if self._recurse is None:
-            raise TypeError(
-                "The loop must have the 'recursive' marker to be called recursively."
-            )
-
-        return self._recurse(iterable, self._recurse, depth=self.depth)
-
-    def __repr__(self):
-        return "<%s %d/%d>" % (self.__class__.__name__, self.index, self.length)
-
-
-class Macro(object):
-    """Wraps a macro function."""
-
-    def __init__(
-        self,
-        environment,
-        func,
-        name,
-        arguments,
-        catch_kwargs,
-        catch_varargs,
-        caller,
-        default_autoescape=None,
-    ):
-        self._environment = environment
-        self._func = func
-        self._argument_count = len(arguments)
-        self.name = name
-        self.arguments = arguments
-        self.catch_kwargs = catch_kwargs
-        self.catch_varargs = catch_varargs
-        self.caller = caller
-        self.explicit_caller = "caller" in arguments
-        if default_autoescape is None:
-            default_autoescape = environment.autoescape
-        self._default_autoescape = default_autoescape
-
-    @internalcode
-    @evalcontextfunction
-    def __call__(self, *args, **kwargs):
-        # This requires a bit of explanation,  In the past we used to
-        # decide largely based on compile-time information if a macro is
-        # safe or unsafe.  While there was a volatile mode it was largely
-        # unused for deciding on escaping.  This turns out to be
-        # problematic for macros because whether a macro is safe depends not
-        # on the escape mode when it was defined, but rather when it was used.
-        #
-        # Because however we export macros from the module system and
-        # there are historic callers that do not pass an eval context (and
-        # will continue to not pass one), we need to perform an instance
-        # check here.
-        #
-        # This is considered safe because an eval context is not a valid
-        # argument to callables otherwise anyway.  Worst case here is
-        # that if no eval context is passed we fall back to the compile
-        # time autoescape flag.
-        if args and isinstance(args[0], EvalContext):
-            autoescape = args[0].autoescape
-            args = args[1:]
-        else:
-            autoescape = self._default_autoescape
-
-        # try to consume the positional arguments
-        arguments = list(args[: self._argument_count])
-        off = len(arguments)
-
-        # For information why this is necessary refer to the handling
-        # of caller in the `macro_body` handler in the compiler.
-        found_caller = False
-
-        # if the number of arguments consumed is not the number of
-        # arguments expected we start filling in keyword arguments
-        # and defaults.
-        if off != self._argument_count:
-            for name in self.arguments[len(arguments) :]:
-                try:
-                    value = kwargs.pop(name)
-                except KeyError:
-                    value = missing
-                if name == "caller":
-                    found_caller = True
-                arguments.append(value)
-        else:
-            found_caller = self.explicit_caller
-
-        # it's important that the order of these arguments does not change
-        # if not also changed in the compiler's `function_scoping` method.
-        # the order is caller, keyword arguments, positional arguments!
-        if self.caller and not found_caller:
-            caller = kwargs.pop("caller", None)
-            if caller is None:
-                caller = self._environment.undefined("No caller defined", name="caller")
-            arguments.append(caller)
-
-        if self.catch_kwargs:
-            arguments.append(kwargs)
-        elif kwargs:
-            if "caller" in kwargs:
-                raise TypeError(
-                    "macro %r was invoked with two values for "
-                    "the special caller argument.  This is "
-                    "most likely a bug." % self.name
-                )
-            raise TypeError(
-                "macro %r takes no keyword argument %r"
-                % (self.name, next(iter(kwargs)))
-            )
-        if self.catch_varargs:
-            arguments.append(args[self._argument_count :])
-        elif len(args) > self._argument_count:
-            raise TypeError(
-                "macro %r takes not more than %d argument(s)"
-                % (self.name, len(self.arguments))
-            )
-
-        return self._invoke(arguments, autoescape)
-
-    def _invoke(self, arguments, autoescape):
-        """This method is being swapped out by the async implementation."""
-        rv = self._func(*arguments)
-        if autoescape:
-            rv = Markup(rv)
-        return rv
-
-    def __repr__(self):
-        return "<%s %s>" % (
-            self.__class__.__name__,
-            self.name is None and "anonymous" or repr(self.name),
-        )
-
-
-@implements_to_string
-class Undefined(object):
-    """The default undefined type.  This undefined type can be printed and
-    iterated over, but every other access will raise an :exc:`UndefinedError`:
-
-    >>> foo = Undefined(name='foo')
-    >>> str(foo)
-    ''
-    >>> not foo
-    True
-    >>> foo + 42
-    Traceback (most recent call last):
-      ...
-    jinja2.exceptions.UndefinedError: 'foo' is undefined
-    """
-
-    __slots__ = (
-        "_undefined_hint",
-        "_undefined_obj",
-        "_undefined_name",
-        "_undefined_exception",
-    )
-
-    def __init__(self, hint=None, obj=missing, name=None, exc=UndefinedError):
-        self._undefined_hint = hint
-        self._undefined_obj = obj
-        self._undefined_name = name
-        self._undefined_exception = exc
-
-    @property
-    def _undefined_message(self):
-        """Build a message about the undefined value based on how it was
-        accessed.
-        """
-        if self._undefined_hint:
-            return self._undefined_hint
-
-        if self._undefined_obj is missing:
-            return "%r is undefined" % self._undefined_name
-
-        if not isinstance(self._undefined_name, string_types):
-            return "%s has no element %r" % (
-                object_type_repr(self._undefined_obj),
-                self._undefined_name,
-            )
-
-        return "%r has no attribute %r" % (
-            object_type_repr(self._undefined_obj),
-            self._undefined_name,
-        )
-
-    @internalcode
-    def _fail_with_undefined_error(self, *args, **kwargs):
-        """Raise an :exc:`UndefinedError` when operations are performed
-        on the undefined value.
-        """
-        raise self._undefined_exception(self._undefined_message)
-
-    @internalcode
-    def __getattr__(self, name):
-        if name[:2] == "__":
-            raise AttributeError(name)
-        return self._fail_with_undefined_error()
-
-    __add__ = (
-        __radd__
-    ) = (
-        __mul__
-    ) = (
-        __rmul__
-    ) = (
-        __div__
-    ) = (
-        __rdiv__
-    ) = (
-        __truediv__
-    ) = (
-        __rtruediv__
-    ) = (
-        __floordiv__
-    ) = (
-        __rfloordiv__
-    ) = (
-        __mod__
-    ) = (
-        __rmod__
-    ) = (
-        __pos__
-    ) = (
-        __neg__
-    ) = (
-        __call__
-    ) = (
-        __getitem__
-    ) = (
-        __lt__
-    ) = (
-        __le__
-    ) = (
-        __gt__
-    ) = (
-        __ge__
-    ) = (
-        __int__
-    ) = (
-        __float__
-    ) = (
-        __complex__
-    ) = __pow__ = __rpow__ = __sub__ = __rsub__ = _fail_with_undefined_error
-
-    def __eq__(self, other):
-        return type(self) is type(other)
-
-    def __ne__(self, other):
-        return not self.__eq__(other)
-
-    def __hash__(self):
-        return id(type(self))
-
-    def __str__(self):
-        return u""
-
-    def __len__(self):
-        return 0
-
-    def __iter__(self):
-        if 0:
-            yield None
-
-    def __nonzero__(self):
-        return False
-
-    __bool__ = __nonzero__
-
-    def __repr__(self):
-        return "Undefined"
-
-
-def make_logging_undefined(logger=None, base=None):
-    """Given a logger object this returns a new undefined class that will
-    log certain failures.  It will log iterations and printing.  If no
-    logger is given a default logger is created.
-
-    Example::
-
-        logger = logging.getLogger(__name__)
-        LoggingUndefined = make_logging_undefined(
-            logger=logger,
-            base=Undefined
-        )
-
-    .. versionadded:: 2.8
-
-    :param logger: the logger to use.  If not provided, a default logger
-                   is created.
-    :param base: the base class to add logging functionality to.  This
-                 defaults to :class:`Undefined`.
-    """
-    if logger is None:
-        import logging
-
-        logger = logging.getLogger(__name__)
-        logger.addHandler(logging.StreamHandler(sys.stderr))
-    if base is None:
-        base = Undefined
-
-    def _log_message(undef):
-        if undef._undefined_hint is None:
-            if undef._undefined_obj is missing:
-                hint = "%s is undefined" % undef._undefined_name
-            elif not isinstance(undef._undefined_name, string_types):
-                hint = "%s has no element %s" % (
-                    object_type_repr(undef._undefined_obj),
-                    undef._undefined_name,
-                )
-            else:
-                hint = "%s has no attribute %s" % (
-                    object_type_repr(undef._undefined_obj),
-                    undef._undefined_name,
-                )
-        else:
-            hint = undef._undefined_hint
-        logger.warning("Template variable warning: %s", hint)
-
-    class LoggingUndefined(base):
-        def _fail_with_undefined_error(self, *args, **kwargs):
-            try:
-                return base._fail_with_undefined_error(self, *args, **kwargs)
-            except self._undefined_exception as e:
-                logger.error("Template variable error: %s", str(e))
-                raise e
-
-        def __str__(self):
-            rv = base.__str__(self)
-            _log_message(self)
-            return rv
-
-        def __iter__(self):
-            rv = base.__iter__(self)
-            _log_message(self)
-            return rv
-
-        if PY2:
-
-            def __nonzero__(self):
-                rv = base.__nonzero__(self)
-                _log_message(self)
-                return rv
-
-            def __unicode__(self):
-                rv = base.__unicode__(self)
-                _log_message(self)
-                return rv
-
-        else:
-
-            def __bool__(self):
-                rv = base.__bool__(self)
-                _log_message(self)
-                return rv
-
-    return LoggingUndefined
-
-
-# No @implements_to_string decorator here because __str__
-# is not overwritten from Undefined in this class.
-# This would cause a recursion error in Python 2.
-class ChainableUndefined(Undefined):
-    """An undefined that is chainable, where both ``__getattr__`` and
-    ``__getitem__`` return itself rather than raising an
-    :exc:`UndefinedError`.
-
-    >>> foo = ChainableUndefined(name='foo')
-    >>> str(foo.bar['baz'])
-    ''
-    >>> foo.bar['baz'] + 42
-    Traceback (most recent call last):
-      ...
-    jinja2.exceptions.UndefinedError: 'foo' is undefined
-
-    .. versionadded:: 2.11.0
-    """
-
-    __slots__ = ()
-
-    def __html__(self):
-        return self.__str__()
-
-    def __getattr__(self, _):
-        return self
-
-    __getitem__ = __getattr__
-
-
-@implements_to_string
-class DebugUndefined(Undefined):
-    """An undefined that returns the debug info when printed.
-
-    >>> foo = DebugUndefined(name='foo')
-    >>> str(foo)
-    '{{ foo }}'
-    >>> not foo
-    True
-    >>> foo + 42
-    Traceback (most recent call last):
-      ...
-    jinja2.exceptions.UndefinedError: 'foo' is undefined
-    """
-
-    __slots__ = ()
-
-    def __str__(self):
-        if self._undefined_hint is None:
-            if self._undefined_obj is missing:
-                return u"{{ %s }}" % self._undefined_name
-            return "{{ no such element: %s[%r] }}" % (
-                object_type_repr(self._undefined_obj),
-                self._undefined_name,
-            )
-        return u"{{ undefined value printed: %s }}" % self._undefined_hint
-
-
-@implements_to_string
-class StrictUndefined(Undefined):
-    """An undefined that barks on print and iteration as well as boolean
-    tests and all kinds of comparisons.  In other words: you can do nothing
-    with it except checking if it's defined using the `defined` test.
-
-    >>> foo = StrictUndefined(name='foo')
-    >>> str(foo)
-    Traceback (most recent call last):
-      ...
-    jinja2.exceptions.UndefinedError: 'foo' is undefined
-    >>> not foo
-    Traceback (most recent call last):
-      ...
-    jinja2.exceptions.UndefinedError: 'foo' is undefined
-    >>> foo + 42
-    Traceback (most recent call last):
-      ...
-    jinja2.exceptions.UndefinedError: 'foo' is undefined
-    """
-
-    __slots__ = ()
-    __iter__ = (
-        __str__
-    ) = (
-        __len__
-    ) = (
-        __nonzero__
-    ) = __eq__ = __ne__ = __bool__ = __hash__ = Undefined._fail_with_undefined_error
-
-
-# remove remaining slots attributes, after the metaclass did the magic they
-# are unneeded and irritating as they contain wrong data for the subclasses.
-del (
-    Undefined.__slots__,
-    ChainableUndefined.__slots__,
-    DebugUndefined.__slots__,
-    StrictUndefined.__slots__,
-)