def update(self, style_sheet=values.unset):
        """
        Update the StyleSheetInstance

        :param dict style_sheet: The JSON string that describes the style sheet object

        :returns: Updated StyleSheetInstance
        :rtype: twilio.rest.autopilot.v1.assistant.style_sheet.StyleSheetInstance
        """
        return self._proxy.update(style_sheet=style_sheet, )