Python和Praw中的异常处理

Question

我在使用以下代码时遇到麻烦：import prawimport argparse# argument handling was heredef main():    r = praw.Reddit(user_agent='Python Reddit Image Grabber v0.1')    for i in range(len(args.subreddits)):        try:            r.get_subreddit(args.subreddits[i]) # test to see if the subreddit is valid        except:            print "Invalid subreddit"        else:            submissions = r.get_subreddit(args.subreddits[i]).get_hot(limit=100)            print [str(x) for x in submissions]if __name__ == '__main__':    main()subreddit 名称被用作程序的参数。当将无效args.subreddits值传递给时get_subreddit，它会引发一个异常，该异常应在上述代码中捕获。当args.subreddit给定有效名称作为参数时，程序可以正常运行。但是，当给出无效args.subreddit名称时，不会引发该异常，而是输出以下未捕获的异常。Traceback (most recent call last):  File "./pyrig.py", line 33, in <module>    main()  File "./pyrig.py", line 30, in main    print [str(x) for x in submissions]  File "/usr/local/lib/python2.7/dist-packages/praw/__init__.py", line 434, in get_content    page_data = self.request_json(url, params=params)  File "/usr/local/lib/python2.7/dist-packages/praw/decorators.py", line 95, in wrapped    return_value = function(reddit_session, *args, **kwargs)  File "/usr/local/lib/python2.7/dist-packages/praw/__init__.py", line 469, in request_json    response = self._request(url, params, data)  File "/usr/local/lib/python2.7/dist-packages/praw/__init__.py", line 342, in _request    response = handle_redirect()  File "/usr/local/lib/python2.7/dist-packages/praw/__init__.py", line 316, in handle_redirect    url = _raise_redirect_exceptions(response)  File "/usr/local/lib/python2.7/dist-packages/praw/internal.py", line 165, in _raise_redirect_exceptions    .format(subreddit))praw.errors.InvalidSubreddit: `soccersdsd` is not a valid subreddit我不知道我在做什么错。我也尝试将异常代码重写为except praw.errors.InvalidSubreddit:这也不起作用。