docs: def from_flag(cls, flag):
          """
          Find relation implementation in the current charm, based on the
          name of an active flag.
  
          You should not use this method directly.
          Use :func:`endpoint_from_flag` instead.
          """
          value = _get_flag_value(flag)
          if value is None:
              return None
          relation_name = value['relation']
          conversations = Conversation.load(value['conversations'])
          return cls.from_name(relation_name, conversations)