code: func (msg *MsgTx) HasWitness() bool {
  	for _, txIn := range msg.TxIn {
  		if len(txIn.Witness) != 0 {
  			return true
  		}
  	}
  
  	return false
  }
docs: // HasWitness returns false if none of the inputs within the transaction
  // contain witness data, true false otherwise.