code: func (dd *xlsxCellDataValidation) SetRange(f1, f2 int, t DataValidationType, o DataValidationOperator) error {
  	formula1 := fmt.Sprintf("%d", f1)
  	formula2 := fmt.Sprintf("%d", f2)
  
  	switch o {
  	case DataValidationOperatorBetween:
  		if f1 > f2 {
  			tmp := formula1
  			formula1 = formula2
  			formula2 = tmp
  		}
  	case DataValidationOperatorNotBetween:
  		if f1 > f2 {
  			tmp := formula1
  			formula1 = formula2
  			formula2 = tmp
  		}
  	}
  
  	dd.Formula1 = formula1
  	dd.Formula2 = formula2
  	dd.Type = convDataValidationType(t)
  	dd.Operator = convDataValidationOperatior(o)
  	return nil
  }
docs: // SetDropList data validation range