code: def get_external_host_tags(self):
          
          self.log.debug("Sending external_host_tags now")
          external_host_tags = []
          for instance in self.instances:
              i_key = self._instance_key(instance)
              if not self.mor_cache.contains(i_key):
                  self.log.warning("Unable to extract host tags for vSphere instance: {}".format(i_key))
                  continue
  
              for _, mor in self.mor_cache.mors(i_key):
                  # Note: some mors have a None hostname
                  hostname = mor.get('hostname')
                  if hostname:
                      external_host_tags.append((hostname, {SOURCE_TYPE: mor.get('tags')}))
  
          return external_host_tags
docs: Returns a list of tags for every host that is detected by the vSphere
          integration.
  
          Returns a list of pairs (hostname, {'SOURCE_TYPE: list_of_tags},)