jinja2.sandbox.modifies_known_mutable¶

jinja2.sandbox.modifies_known_mutable(obj, attr)[source]¶

This function checks if an attribute on a builtin mutable object (list, dict, set or deque) would modify it if called. It also supports the “user”-versions of the objects (sets.Set, UserDict.* etc.) and with Python 2.6 onwards the abstract base classes MutableSet, MutableMapping, and MutableSequence.

>>> modifies_known_mutable({}, "clear")
True
>>> modifies_known_mutable({}, "keys")
False
>>> modifies_known_mutable([], "append")
True
>>> modifies_known_mutable([], "index")
False

If called with an unsupported object (such as unicode) False is returned.

>>> modifies_known_mutable("foo", "upper")
False