code: func (s *GlobalStore) HasKey(addr common.Address, key []byte) bool {
  	var has bool
  	if err := s.client.Call(&has, "mockStore_hasKey", addr, key); err != nil {
  		log.Error(fmt.Sprintf("mock store HasKey: addr %s, key %064x: %v", addr, key, err))
  		return false
  	}
  	return has
  }
docs: // HasKey calls a HasKey method to RPC server.