code: func (fs FrontierSigner) Hash(tx *Transaction) common.Hash {
  	return rlpHash([]interface{}{
  		tx.data.AccountNonce,
  		tx.data.Price,
  		tx.data.GasLimit,
  		tx.data.Recipient,
  		tx.data.Amount,
  		tx.data.Payload,
  	})
  }
docs: // Hash returns the hash to be signed by the sender.
  // It does not uniquely identify the transaction.