code: def update_validity(self):
          
  
          # WM is always valid
          if self.type == 'Hypermap:WorldMap':
              return
  
          signals.post_save.disconnect(service_post_save, sender=Service)
  
          try:
  
              # some service now must be considered invalid:
              # 0. any service not exposed in SUPPORTED_SRS
              # 1. any WMTS service
              # 2. all of the NOAA layers
  
              is_valid = True
  
              # 0. any service not exposed in SUPPORTED_SRS
              if self.srs.filter(code__in=SUPPORTED_SRS).count() == 0:
                  LOGGER.debug('Service with id %s is marked invalid because in not exposed in SUPPORTED_SRS' % self.id)
                  is_valid = False
  
              # 1. any WMTS service
              if self.type == 'OGC:WMTS':
                  LOGGER.debug('Service with id %s is marked invalid because it is of type OGC:WMTS' % self.id)
                  is_valid = False
  
              # 2. all of the NOAA layers
              if 'noaa' in self.url.lower():
                  LOGGER.debug('Service with id %s is marked invalid because it is from NOAA' % self.id)
                  is_valid = False
  
              # now we save the service
              self.is_valid = is_valid
              self.save()
  
          except:
              LOGGER.error('Error updating validity of the service!')
  
          signals.post_save.connect(service_post_save, sender=Service)
docs: Update validity of a service.