code: def exists(self):
          
          try:
              key = self.key
          except DoesNotExist:
              """
              If the object doesn't exists anymore, its PK is deleted, so the
              "self.key" call will raise a DoesNotExist exception. We catch it
              to return False, as the field doesn't exists too.
              """
              return False
          else:
              return self.connection.exists(key)
docs: Call the exists command to check if the redis key exists for the current
          field