def get_dir_from_zipfile(zip_file, fallback=None):
    """Return the name of the root folder in a zip file.

    :param zip_file: a :class:`zipfile.ZipFile` instance.
    :param fallback: if `None`, the name of the zip file is used. This is
        returned if the zip file contains more than one top-level directory,
        or none at all.
    """
    fallback = fallback or zip_file.filename
    directories = [name for name in zip_file.namelist() if name.endswith("/")
                   and len(PurePath(name).parts) == 1]
    return fallback if len(directories) > 1 else directories[0]
def test_filter_factory(self):
        factory = memcache.filter_factory({'max_connections': '3'},
                                          memcache_servers='10.10.10.10:10',
                                          memcache_serialization_support='1')
        thefilter = factory('myapp')
        self.assertEqual(thefilter.app, 'myapp')
        self.assertEqual(thefilter.memcache_servers, '10.10.10.10:10')
        self.assertEqual(thefilter.memcache._allow_pickle, False)
        self.assertEqual(thefilter.memcache._allow_unpickle, True)
        self.assertEqual(
            thefilter.memcache._client_cache['10.10.10.10:10'].max_size, 3)