code: func (v *CssProvider) LoadFromData(data string) error {
  	cdata := C.CString(data)
  	defer C.free(unsafe.Pointer(cdata))
  	var gerr *C.GError
  	if C.gtk_css_provider_load_from_data(v.native(), (*C.gchar)(unsafe.Pointer(cdata)), C.gssize(len(data)), &gerr) == 0 {
  		defer C.g_error_free(gerr)
  		return errors.New(goString(gerr.message))
  	}
  	return nil
  }
docs: // LoadFromData is a wrapper around gtk_css_provider_load_from_data().