code: def merge_extinfo(service, extinfo):
          
          properties = ['notes', 'notes_url', 'icon_image', 'icon_image_alt']
          # service properties have precedence over serviceextinfo properties
          for prop in properties:
              if getattr(service, prop) == '' and getattr(extinfo, prop) != '':
                  setattr(service, prop, getattr(extinfo, prop))
docs: Merge extended host information into a service
  
          :param service: the service to edit
          :type service: alignak.objects.service.Service
          :param extinfo: the external info we get data from
          :type extinfo: alignak.objects.serviceextinfo.ServiceExtInfo
          :return: None