Mercurial > hg
view mercurial/thirdparty/attr/converters.py @ 37578:56df2ca5c032
py3: prevent transformer from adding b'' by adding r'' prefix
These are cases where we need to use str, therefore we add r'' prefix.
# skip-blame because just r'' prefixes
Differential Revision: https://phab.mercurial-scm.org/D3276
author | Pulkit Goyal <7895pulkit@gmail.com> |
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date | Thu, 12 Apr 2018 14:28:08 +0530 |
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