)

// ExpirationDays is a type alias to unmarshal Days in Expiration
type ExpirationDays int

// UnmarshalXML parses number of days from Expiration and validates if
// greater than zero
func (eDays *ExpirationDays) UnmarshalXML(d *xml.Decoder, startElement xml.StartElement) error {
	var numDays int
	err := d.DecodeElement(&numDays, &startElement)
	if err != nil {
		return err
	}