code: func (ps *PrintSettings) SetMediaType(mediaType string) {
  	cstr := C.CString(mediaType)
  	defer C.free(unsafe.Pointer(cstr))
  	C.gtk_print_settings_set_media_type(ps.native(), (*C.gchar)(cstr))
  }
docs: // SetMediaType() is a wrapper around gtk_print_settings_set_media_type().