return e.Days == ExpirationDays(0)
}

// IsDateNull returns true if date field is null
func (e Expiration) IsDateNull() bool {
	return e.Date.Time.IsZero()
}

// IsNull returns true if both date and days fields are null
func (e Expiration) IsNull() bool {
	return e.IsDaysNull() && e.IsDateNull()