code: def __len__(self) -> int:
      return len(self.parties)
  
imports: import logging
  import typing
  from typing import List, Tuple, TypeVar, Union
  from fate.arch.federation.api import PartyMeta, TableRemotePersistentPickler, TableRemotePersistentUnpickler
  from fate.arch.trace import federation_get_timer, federation_remote_timer
  from ._namespace import NS
label_desc: Use image node_id 6 for calling the Parties obj's underlying member method code with example usage: obj.__len__() and returns: len