code: def get_number_of_current_players(self, appID, format=None):
          
          parameters = {'appid' : appID}
          if format is not None:
              parameters['format'] = format
          url = self.create_request_url(self.interface,
              'GetNumberOfCurrentPlayers', 1, parameters)
          data = self.retrieve_request(url)
          return self.return_data(data, format=format)
docs: Request the current number of players for a given app.
  
          appID: The app ID
          format: Return format. None defaults to json. (json, xml, vdf)