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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 get_user_tweets(self, auth_secret, username, max_cnt_tweets):
 """Get the tweets posted by one user. Parameters auth_secret: str The authentication secret of the logged-in user. username: The name of the user who post the tweets and may not be the logged-in user. max_cnt_tweets: int The maximum number of tweets included in the return. If it is set to -1, then all the tweets posted by the user will be included. Returns ------- bool True if the tweets are successfully retrieved, False otherwise. result A dict containing a list of tweets with the key TWEETS_KEY if the tweets are successfully retrieved, a dict containing the error string with the key ERROR_KEY otherwise. Note ---- Possible error strings are listed as below: - ERROR_NOT_LOGGED_IN - ERROR_USERNAME_NOT_EXIST_FORMAT.format(username) """

        result = {pytwis_constants.ERROR_KEY: None}

        # Check if the user is logged in.
        loggedin, _ = self._is_loggedin(auth_secret)
        if not loggedin:
            result[pytwis_constants.ERROR_KEY] = pytwis_constants.ERROR_NOT_LOGGED_IN
            return (False, result)

        # Get the userid from the username.
        userid = self._rc.hget(pytwis_constants.USERS_KEY, username)
        if userid is None:
            result[pytwis_constants.ERROR_KEY] = \
                pytwis_constants.ERROR_USERNAME_NOT_EXIST_FORMAT.format(username)
            return (False, result)

        # Get the tweets posted by the user.
        user_tweets_key = pytwis_constants.USER_TWEETS_KEY_FORMAT.format(userid)

        result[pytwis_constants.TWEETS_KEY] = \
            self._get_tweets(user_tweets_key, max_cnt_tweets)
        return (True, result)