Set webhook for bot

        :param webhook_path: Optional[str] (default: None)
        :param request_handler: Any (default: WebhookRequestHandler)
        :param route_name: str Name of webhook handler route (default: 'webhook_handler')
        :param web_app: Optional[Application] (default: None)
        :return:

def set_webhook(self, webhook_path: Optional[str] = None, request_handler: Any = WebhookRequestHandler,
                    route_name: str = DEFAULT_ROUTE_NAME, web_app: Optional[Application] = None):
        """
        Set webhook for bot

        :param webhook_path: Optional[str] (default: None)
        :param request_handler: Any (default: WebhookRequestHandler)
        :param route_name: str Name of webhook handler route (default: 'webhook_handler')
        :param web_app: Optional[Application] (default: None)
        :return:
        """
        self._prepare_webhook(webhook_path, request_handler, route_name, web_app)
        self.loop.run_until_complete(self._startup_webhook())