Mercurial > hg
view mercurial/thirdparty/attr/converters.py @ 37472:2f81926c7f89
wireproto: fix repr(frame) to not crash by unknown type id
Follows up 5ef2da00e935.
author | Yuya Nishihara <yuya@tcha.org> |
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date | Sun, 08 Apr 2018 11:14:47 +0900 |
parents | 765eb17a7eb8 |
children | e1c586b9a43c |
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""" 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