39 lines
1.1 KiB
Python
39 lines
1.1 KiB
Python
# 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", (), {})
|