code: def schedule_hostgroup_svc_downtime(self, hostgroup, start_time, end_time, fixed,
                                          trigger_id, duration, author, comment):
          
          for host_id in hostgroup.get_hosts():
              if host_id in self.daemon.hosts:
                  host = self.daemon.hosts[host_id]
                  for service_id in host.services:
                      service = self.daemon.services[service_id]
                      self.schedule_svc_downtime(service, start_time, end_time, fixed,
                                                 trigger_id, duration, author, comment)
docs: Schedule a downtime for each service of each host of a hostgroup
          Format of the line that triggers function call::
  
          SCHEDULE_HOSTGROUP_SVC_DOWNTIME;;<hostgroup_name>;<start_time>;<end_time>;<fixed>;
          <trigger_id>;<duration>;<author>;<comment>
  
          :param hostgroup: hostgroup to schedule
          :type hostgroup: alignak.objects.hostgroup.Hostgroup
          :param start_time: downtime start time
          :type start_time:
          :param end_time: downtime end time
          :type end_time:
          :param fixed: is downtime fixed
          :type fixed:
          :param trigger_id: downtime id that triggered this one
          :type trigger_id: str
          :param duration: downtime duration
          :type duration: int
          :param author: downtime author
          :type author: str
          :param comment: downtime comment
          :type comment: str
          :return: None