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Solve the following problem using Python, implementing the functions described below, one line at a time
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Description:
 def comment_stream(reddit_session, subreddit, limit=None, verbosity=1):
 """Indefinitely yield new comments from the provided subreddit. Comments are yielded from oldest to newest. :param reddit_session: The reddit_session to make requests from. In all the examples this is assigned to the variable ``r``. :param subreddit: Either a subreddit object, or the name of a subreddit. Use `all` to get the comment stream for all comments made to reddit. :param limit: The maximum number of comments to fetch in a single iteration. When None, fetch all available comments (reddit limits this to 1000 (or multiple of 1000 for multi-subreddits). If this number is too small, comments may be missed. :param verbosity: A number that controls the amount of output produced to stderr. <= 0: no output; >= 1: output the total number of comments processed and provide the short-term number of comments processed per second; >= 2: output when additional delays are added in order to avoid subsequent unexpected http errors. >= 3: output debugging information regarding the comment stream. (Default: 1) """

    get_function = partial(reddit_session.get_comments,
                           six.text_type(subreddit))
    return _stream_generator(get_function, limit, verbosity)