code: def _num_players(self):
          
          self._player_num = 0
          self._computer_num = 0
          for player in self._header.scenario.game_settings.player_info:
              if player.type == 'human':
                  self._player_num += 1
              elif player.type == 'computer':
                  self._computer_num += 1
docs: Compute number of players, both human and computer.