code: def purge_cache(self, object_type):
          
          if object_type in self.mapping:
              cache = self.mapping[object_type]
              log.debug("Purging [{}] cache of {} values.".format(object_type, len(cache)))
              cache.purge()
docs: Purge the named cache of all values. If no cache exists for object_type, nothing is done