code: func NewResult(operation Operation, result Result, errMsg ...string) *OperationResult {
  	msg := ""
  	if len(errMsg) > 0 {
  		msg = errMsg[0]
  	}
  	return &OperationResult{
  		Operation:  operation,
  		Result:     result,
  		ErrMessage: msg,
  	}
  }
docs: // NewResult returns a new OperationResult