code: func isScriptHash(script []byte) (bool, []byte) {
  	if len(script) == 23 && script[0] == txscript.OP_HASH160 &&
  		script[1] == txscript.OP_DATA_20 &&
  		script[22] == txscript.OP_EQUAL {
  
  		return true, script[2:22]
  	}
  
  	return false, nil
  }
docs: // isScriptHash returns whether or not the passed public key script is a
  // standard pay-to-script-hash script along with the script hash it is paying to
  // if it is.