django-rest-auth/rest_auth/utils.py

from six import string_types
from importlib import import_module


def import_callable(path_or_callable):
    if hasattr(path_or_callable, '__call__'):
        return path_or_callable
    else:
        assert isinstance(path_or_callable, string_types)
        package, attr = path_or_callable.rsplit('.', 1)
        return getattr(import_module(package), attr)