code: def linkify_es_by_s(self, services):
          
          for escalation in self:
              # If no host, no hope of having a service
              if not hasattr(escalation, 'host_name'):
                  continue
  
              es_hname, sdesc = escalation.host_name, escalation.service_description
              if not es_hname.strip() or not sdesc.strip():
                  continue
  
              for hname in strip_and_uniq(es_hname.split(',')):
                  if sdesc.strip() == '*':
                      slist = services.find_srvs_by_hostname(hname)
                      if slist is not None:
                          slist = [services[serv] for serv in slist]
                          for serv in slist:
                              serv.escalations.append(escalation.uuid)
                  else:
                      for sname in strip_and_uniq(sdesc.split(',')):
                          serv = services.find_srv_by_name_and_hostname(hname, sname)
                          if serv is not None:
                              serv.escalations.append(escalation.uuid)
docs: Add each escalation object into service.escalation attribute
  
          :param services: service list, used to look for a specific service
          :type services: alignak.objects.service.Services
          :return: None