Add a widget to the customization.

        Will save the widget to KE-chain.

        :param widget: The widget (specific json dict) to be added
        :type widget: dict

def _add_widget(self, widget):
        """
        Add a widget to the customization.

        Will save the widget to KE-chain.

        :param widget: The widget (specific json dict) to be added
        :type widget: dict
        """
        widgets = self.widgets()
        widgets += [widget]
        self._save_customization(widgets)