code: func (self *stateObject) Code(db Database) []byte {
  	if self.code != nil {
  		return self.code
  	}
  	if bytes.Equal(self.CodeHash(), emptyCodeHash) {
  		return nil
  	}
  	code, err := db.ContractCode(self.addrHash, common.BytesToHash(self.CodeHash()))
  	if err != nil {
  		self.setError(fmt.Errorf("can't load code hash %x: %v", self.CodeHash(), err))
  	}
  	self.code = code
  	return code
  }
docs: // Code returns the contract code associated with this object, if any.