'Get pulbic rooms for a particular list, or across all lists.
Args:
stream_id (int)
network_tuple (ThirdPartyInstanceID): The list to use (None, None)
means the main list, None means all lsits.'

@cached(num_args=2, max_entries=100)
def get_public_room_ids_at_stream_id(self, stream_id, network_tuple):

    return self.runInteraction('get_public_room_ids_at_stream_id', self.get_public_room_ids_at_stream_id_txn, stream_id, network_tuple=network_tuple)
