Fetch top submissions by some top value.

        :param top: One of week, month, year, all
        :returns: True if any submissions were found.

def fetch_top_submissions(self, top):
        """Fetch top submissions by some top value.

        :param top: One of week, month, year, all
        :returns: True if any submissions were found.

        """
        for submission in self.subreddit.top(limit=None, time_filter=top):
            self.submissions[submission.id] = MiniSubmission(submission)