code: def hmget(self, *args):
          
          if args and not any(arg in self._instancehash_fields for arg in args):
              raise ValueError("Only InstanceHashField can be used here.")
  
          return self._call_command('hmget', args)
docs: This command on the model allow getting many instancehash fields with only
          one redis call. You must pass hash name to retrieve as arguments.