code: func opcodeHash160(op *parsedOpcode, vm *Engine) error {
  	buf, err := vm.dstack.PopByteArray()
  	if err != nil {
  		return err
  	}
  
  	hash := sha256.Sum256(buf)
  	vm.dstack.PushByteArray(calcHash(hash[:], ripemd160.New()))
  	return nil
  }
docs: // opcodeHash160 treats the top item of the data stack as raw bytes and replaces
  // it with ripemd160(sha256(data)).
  //
  // Stack transformation: [... x1] -> [... ripemd160(sha256(x1))]