pped (``False``). Is called with the `attr.Attribute` as the first argument and the value as the second argument. :param callable dict_factory: A callable to produce dictionaries from. For example, to produce ordered dictionaries instead of normal Python dictionaries, pass in ``collections.OrderedDict``. :param bool retain_collection_types: Do not convert to ``list`` when encountering an attribute whose type is ``tuple`` or ``set``. Only meaningful if ``recurse`` is ``True``. :rtype: return type of *dict_factory* :raise attr.exceptions.NotAnAttrsClassError: If *cls* is not an ``attrs`` class. .. versionadded:: 16.0.0 *dict_factory* .. versionadded:: 16.1.0 *retain_collection_types* NTc