code: def get_check_command(self, timeperiods, t_to_go):
          
          if not self.check_period or timeperiods[self.check_period].is_time_valid(t_to_go):
              return self.check_command
          return None
docs: Get the check_command if we are in the check period modulation
  
          :param t_to_go: time to check if we are in the timeperiod
          :type t_to_go:
          :return: A check command if we are in the check period, None otherwise
          :rtype: alignak.objects.command.Command