| # This file is dual licensed under the terms of the Apache License, Version |
| # 2.0, and the BSD License. See the LICENSE file in the root of this repository |
| # for complete details. |
| from __future__ import absolute_import, division, print_function |
| |
| import sys |
| |
| from ._typing import TYPE_CHECKING |
| |
| if TYPE_CHECKING: # pragma: no cover |
| from typing import Any, Dict, Tuple, Type |
| |
| |
| PY2 = sys.version_info[0] == 2 |
| PY3 = sys.version_info[0] == 3 |
| |
| # flake8: noqa |
| |
| if PY3: |
| string_types = (str,) |
| else: |
| string_types = (basestring,) |
| |
| |
| def with_metaclass(meta, *bases): |
| # type: (Type[Any], Tuple[Type[Any], ...]) -> Any |
| """ |
| Create a base class with a metaclass. |
| """ |
| # This requires a bit of explanation: the basic idea is to make a dummy |
| # metaclass for one level of class instantiation that replaces itself with |
| # the actual metaclass. |
| class metaclass(meta): # type: ignore |
| def __new__(cls, name, this_bases, d): |
| # type: (Type[Any], str, Tuple[Any], Dict[Any, Any]) -> Any |
| return meta(name, bases, d) |
| |
| return type.__new__(metaclass, "temporary_class", (), {}) |
