1# This file is dual licensed under the terms of the Apache License, Version 2# 2.0, and the BSD License. See the LICENSE file in the root of this repository 3# for complete details. 4from __future__ import absolute_import, division, print_function 5 6import sys 7 8 9PY2 = sys.version_info[0] == 2 10PY3 = sys.version_info[0] == 3 11 12# flake8: noqa 13 14if PY3: 15 string_types = str, 16else: 17 string_types = basestring, 18 19 20def with_metaclass(meta, *bases): 21 """ 22 Create a base class with a metaclass. 23 """ 24 # This requires a bit of explanation: the basic idea is to make a dummy 25 # metaclass for one level of class instantiation that replaces itself with 26 # the actual metaclass. 27 class metaclass(meta): 28 def __new__(cls, name, this_bases, d): 29 return meta(name, bases, d) 30 return type.__new__(metaclass, 'temporary_class', (), {}) 31