gtk/print.go
func (ps *PaperSize) IsCustom() bool {
	c := C.gtk_paper_size_is_custom(ps.native())
	return gobool(c)
}
func (ps *PaperSize) IsCustom() bool {
	c := C.gtk_paper_size_is_custom(ps.native())
	return gobool(c)
}
// IsCustom() is a wrapper around gtk_paper_size_is_custom().