Starts the `PrawOAuth2Server` server. It will open the default
        web browser and it will take you to Reddit's authorization page,
        asking you to authorize your Reddit account(or account of the bot's)
        with your app(or bot script). Once authorized successfully, it will
        show `successful` message in web browser.

def start(self):
        """Starts the `PrawOAuth2Server` server. It will open the default
        web browser and it will take you to Reddit's authorization page,
        asking you to authorize your Reddit account(or account of the bot's)
        with your app(or bot script). Once authorized successfully, it will
        show `successful` message in web browser.
        """
        global CODE
        url = self._get_auth_url()
        webbrowser.open(url)
        tornado.ioloop.IOLoop.current().start()
        self.code = CODE