code: func SpinButtonNewWithRange(min, max, step float64) (*SpinButton, error) {
  	c := C.gtk_spin_button_new_with_range(C.gdouble(min), C.gdouble(max),
  		C.gdouble(step))
  	if c == nil {
  		return nil, nilPtrErr
  	}
  	return wrapSpinButton(glib.Take(unsafe.Pointer(c))), nil
  }
docs: // SpinButtonNewWithRange() is a wrapper around
  // gtk_spin_button_new_with_range().