code: def linkify(self, hosts, services, timeperiods):
          
          self.linkify_sd_by_s(hosts, services)
          self.linkify_sd_by_tp(timeperiods)
          self.linkify_s_by_sd(services)
docs: Create link between objects::
  
           * servicedependency -> host
           * servicedependency -> service
           * servicedependency -> timeperiods
  
          :param hosts: hosts to link
          :type hosts: alignak.objects.host.Hosts
          :param services: services to link
          :type services: alignak.objects.service.Services
          :param timeperiods: timeperiods to link
          :type timeperiods: alignak.objects.timeperiod.Timeperiods
          :return: None