def _load_library(self):
        if self.library is not None:
            if isinstance(self.library, (tuple, list)):
                name, mod_path = self.library
            else:
                name = mod_path = self.library
            try:
                module = importlib.import_module(mod_path)
            except __HOLE__:
                raise ValueError("Couldn't load %s password algorithm "
                                 "library" % name)
            return module
        raise ValueError("Hasher '%s' doesn't specify a library attribute" %
                         self.__class__)
dataset/ETHPy150Open AppScale/appscale/AppServer/lib/django-1.4/django/contrib/auth/hashers.py/BasePasswordHasher._load_library