func (u *ISBN13) UnmarshalText(data []byte) error { // validation is performed later on
	*u = ISBN13(string(data))
	return nil
}
func (u *ISBN13) UnmarshalText(data []byte) error { // validation is performed later on
	*u = ISBN13(string(data))
	return nil
}
// UnmarshalText hydrates this instance from text