Remove windows python distribution from repo and add requirements.txt

1 files changed, 0 insertions, 813 deletions

diff --git a/python/jinja2/runtime.py b/python/jinja2/runtime.py
deleted file mode 100644
index f9d7a68..0000000
--- a/python/jinja2/runtime.py
+++ /dev/null
@@ -1,813 +0,0 @@
-# -*- coding: utf-8 -*-
-"""
-    jinja2.runtime
-    ~~~~~~~~~~~~~~
-
-    Runtime helpers.
-
-    :copyright: (c) 2017 by the Jinja Team.
-    :license: BSD.
-"""
-import sys
-
-from itertools import chain
-from types import MethodType
-
-from jinja2.nodes import EvalContext, _context_function_types
-from jinja2.utils import Markup, soft_unicode, escape, missing, concat, \
-     internalcode, object_type_repr, evalcontextfunction, Namespace
-from jinja2.exceptions import UndefinedError, TemplateRuntimeError, \
-     TemplateNotFound
-from jinja2._compat import imap, text_type, iteritems, \
-     implements_iterator, implements_to_string, string_types, PY2, \
-     with_metaclass
-
-
-# these variables are exported to the template runtime
-__all__ = ['LoopContext', 'TemplateReference', 'Macro', 'Markup',
-           'TemplateRuntimeError', 'missing', 'concat', 'escape',
-           'markup_join', 'unicode_join', 'to_string', 'identity',
-           'TemplateNotFound', 'Namespace']
-
-#: 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
-
-#: the identity function.  Useful for certain things in the environment
-identity = lambda x: x
-
-_first_iteration = object()
-_last_iteration = object()
-
-
-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 to 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__(cls, name, bases, d):
-        rv = type.__new__(cls, 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):
-        """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__'):
-            fn = __obj.__call__
-            for fn_type in ('contextfunction',
-                            'evalcontextfunction',
-                            'environmentfunction'):
-                if hasattr(fn, fn_type):
-                    __obj = fn
-                    break
-
-        if isinstance(__obj, _context_function_types):
-            if getattr(__obj, 'contextfunction', 0):
-                args = (__self,) + args
-            elif getattr(__obj, 'evalcontextfunction', 0):
-                args = (__self.eval_ctx,) + args
-            elif getattr(__obj, 'environmentfunction', 0):
-                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):
-        proxy = lambda self: 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
-        )
-
-
-# register the context as mapping if possible
-try:
-    from collections import Mapping
-    Mapping.register(Context)
-except ImportError:
-    pass
-
-
-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
-
-
-class LoopContextBase(object):
-    """A loop context for dynamic iteration."""
-
-    _before = _first_iteration
-    _current = _first_iteration
-    _after = _last_iteration
-    _length = None
-
-    def __init__(self, undefined, recurse=None, depth0=0):
-        self._undefined = undefined
-        self._recurse = recurse
-        self.index0 = -1
-        self.depth0 = depth0
-        self._last_checked_value = missing
-
-    def cycle(self, *args):
-        """Cycles among the arguments with the current loop index."""
-        if not args:
-            raise TypeError('no items for cycling given')
-        return args[self.index0 % len(args)]
-
-    def changed(self, *value):
-        """Checks whether the value has changed since the last call."""
-        if self._last_checked_value != value:
-            self._last_checked_value = value
-            return True
-        return False
-
-    first = property(lambda x: x.index0 == 0)
-    last = property(lambda x: x._after is _last_iteration)
-    index = property(lambda x: x.index0 + 1)
-    revindex = property(lambda x: x.length - x.index0)
-    revindex0 = property(lambda x: x.length - x.index)
-    depth = property(lambda x: x.depth0 + 1)
-
-    @property
-    def previtem(self):
-        if self._before is _first_iteration:
-            return self._undefined('there is no previous item')
-        return self._before
-
-    @property
-    def nextitem(self):
-        if self._after is _last_iteration:
-            return self._undefined('there is no next item')
-        return self._after
-
-    def __len__(self):
-        return self.length
-
-    @internalcode
-    def loop(self, iterable):
-        if self._recurse is None:
-            raise TypeError('Tried to call non recursive loop.  Maybe you '
-                            "forgot the 'recursive' modifier.")
-        return self._recurse(iterable, self._recurse, self.depth0 + 1)
-
-    # a nifty trick to enhance the error message if someone tried to call
-    # the the loop without or with too many arguments.
-    __call__ = loop
-    del loop
-
-    def __repr__(self):
-        return '<%s %r/%r>' % (
-            self.__class__.__name__,
-            self.index,
-            self.length
-        )
-
-
-class LoopContext(LoopContextBase):
-
-    def __init__(self, iterable, undefined, recurse=None, depth0=0):
-        LoopContextBase.__init__(self, undefined, recurse, depth0)
-        self._iterator = iter(iterable)
-
-        # try to get the length of the iterable early.  This must be done
-        # here because there are some broken iterators around where there
-        # __len__ is the number of iterations left (i'm looking at your
-        # listreverseiterator!).
-        try:
-            self._length = len(iterable)
-        except (TypeError, AttributeError):
-            self._length = None
-        self._after = self._safe_next()
-
-    @property
-    def length(self):
-        if self._length is None:
-            # if was not possible to get the length of the iterator when
-            # the loop context was created (ie: iterating over a generator)
-            # we have to convert the iterable into a sequence and use the
-            # length of that + the number of iterations so far.
-            iterable = tuple(self._iterator)
-            self._iterator = iter(iterable)
-            iterations_done = self.index0 + 2
-            self._length = len(iterable) + iterations_done
-        return self._length
-
-    def __iter__(self):
-        return LoopContextIterator(self)
-
-    def _safe_next(self):
-        try:
-            return next(self._iterator)
-        except StopIteration:
-            return _last_iteration
-
-
-@implements_iterator
-class LoopContextIterator(object):
-    """The iterator for a loop context."""
-    __slots__ = ('context',)
-
-    def __init__(self, context):
-        self.context = context
-
-    def __iter__(self):
-        return self
-
-    def __next__(self):
-        ctx = self.context
-        ctx.index0 += 1
-        if ctx._after is _last_iteration:
-            raise StopIteration()
-        ctx._before = ctx._current
-        ctx._current = ctx._after
-        ctx._after = ctx._safe_next()
-        return ctx._current, ctx
-
-
-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
-        # problemtic for macros because if a macro is safe or not not so
-        # much depends on the escape mode when it was defined but 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 anwyays.  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 idx, name in enumerate(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:`jinja2.exceptions.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
-
-    @internalcode
-    def _fail_with_undefined_error(self, *args, **kwargs):
-        """Regular callback function for undefined objects that raises an
-        `jinja2.exceptions.UndefinedError` on call.
-        """
-        if self._undefined_hint is None:
-            if self._undefined_obj is missing:
-                hint = '%r is undefined' % self._undefined_name
-            elif not isinstance(self._undefined_name, string_types):
-                hint = '%s has no element %r' % (
-                    object_type_repr(self._undefined_obj),
-                    self._undefined_name
-                )
-            else:
-                hint = '%r has no attribute %r' % (
-                    object_type_repr(self._undefined_obj),
-                    self._undefined_name
-                )
-        else:
-            hint = self._undefined_hint
-        raise self._undefined_exception(hint)
-
-    @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
-
-
-@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__, DebugUndefined.__slots__, StrictUndefined.__slots__