date.go
func (d *Date) UnmarshalText(text []byte) error {
	if len(text) == 0 {
		return nil
	}
	dd, err := time.Parse(RFC3339FullDate, string(text))
	if err != nil {
		return err
	}
	*d = Date(dd)
	return nil
}
func (d *Date) UnmarshalText(text []byte) error {
	if len(text) == 0 {
		return nil
	}
	dd, err := time.Parse(RFC3339FullDate, string(text))
	if err != nil {
		return err
	}
	*d = Date(dd)
	return nil
}
// UnmarshalText parses a text representation into a date type