code: func NewTxSigHashes(tx *wire.MsgTx) *TxSigHashes {
  	return &TxSigHashes{
  		HashPrevOuts: calcHashPrevOuts(tx),
  		HashSequence: calcHashSequence(tx),
  		HashOutputs:  calcHashOutputs(tx),
  	}
  }
docs: // NewTxSigHashes computes, and returns the cached sighashes of the given
  // transaction.