templates: add filter to reverse list
The filter supports only lists because for lists, it’s straightforward to
implement. Reversing text doesn’t seem very useful and is hard to implement.
Reversing the bytes would break multi-bytes encodings. Reversing the code
points would break characters consisting of multiple code points. Reversing
graphemes is non-trivial without using a library not included in the standard
library.
from __future__ import absolute_import, division, print_function
class FrozenInstanceError(AttributeError):
"""
A frozen/immutable instance has been attempted to be modified.
It mirrors the behavior of ``namedtuples`` by using the same error message
and subclassing :exc:`AttributeError`.
.. versionadded:: 16.1.0
"""
msg = "can't set attribute"
args = [msg]
class AttrsAttributeNotFoundError(ValueError):
"""
An ``attrs`` function couldn't find an attribute that the user asked for.
.. versionadded:: 16.2.0
"""
class NotAnAttrsClassError(ValueError):
"""
A non-``attrs`` class has been passed into an ``attrs`` function.
.. versionadded:: 16.2.0
"""
class DefaultAlreadySetError(RuntimeError):
"""
A default has been set using ``attr.ib()`` and is attempted to be reset
using the decorator.
.. versionadded:: 17.1.0
"""