sign method

@override KasTxData sign()

Implementation

@override
KasTxData sign() {
  for (int i = 0; i < txData.inputs.length; i++) {
    txData.messages.add(txData.inputs[i].signatureScript);
    final signautre = wallet.sign(txData.inputs[i].signatureScript);
    txData.inputs[i].signatureScript = addFixs(signautre);
  }
  txData.isSigned = true;
  return txData;
}