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Direktori : /opt/alt/python35/lib/python3.5/site-packages/attr/ |
Current File : //opt/alt/python35/lib/python3.5/site-packages/attr/converters.py |
""" Commonly useful converters. """ from __future__ import absolute_import, division, print_function def optional(converter): """ A converter that allows an attribute to be optional. An optional attribute is one which can be set to ``None``. :param callable converter: the converter that is used for non-``None`` values. .. versionadded:: 17.1.0 """ def optional_converter(val): if val is None: return None return converter(val) return optional_converter