Reddit bot for updating flair to top commenter's username after 48 hours

bot.py

    import sys
    import traceback
    import datetime
    
    import praw
    
    BOT_USERNAME      = 'BOT_USERNAME'
    BOT_PASSWORD      = 'BOT_PASSWORD'
    BOT_CLIENT_ID     = 'BOT_CLIENT_ID'
    BOT_CLIENT_SECRET = 'BOT_CLIENT_SECRET'
    BOT_USER_AGENT    = 'BOT_USER_AGENT'
    
    TARGET_SUBREDDIT  = 'TARGET_SUBREDDIT'
    FLAIR_CSS_CLASS   = ''
    FLAIR_MSG         = 'Questioned by: /u/'
    

    class Bot():
        def __init__(self):
            self.reddit = praw.Reddit(username=BOT_USERNAME,
                                      password=BOT_PASSWORD,
                                      client_id=BOT_CLIENT_ID,
                                      client_secret=BOT_CLIENT_SECRET,
                                      user_agent=BOT_USER_AGENT)
            self.new_submissions = []

        def botcode(self):
            try:
                for submission in self.reddit.subreddit(TARGET_SUBREDDIT).stream.submissions(skip_existing=True):
                    self.new_submissions.append(submission)

                    carryover_submissions = []
                    for submission in self.new_submissions:
                        if self.date_diff_in_hours(submission.created_utc) < 48:
                            carryover_submissions.append(submission)
                            continue

                        submission.comment_sort = 'best'
                        top_comment = [ comment for comment in submission.comments ][0]
                        top_commenter = top_comment.redditor.name
                        flair_id = [ choice['id'] for choice in submission.link_flair.choices() if choice['css_class'] == FLAIR_CSS_CLASS ][0]

                        submission.flair.select(flair_id, FLAIR_MSG + top_commenter)

                    self.new_submissions = carryover_submissions

            except BaseException as e:
                if type(e) == KeyboardInterrupt:
                    sys.exit(0)
                else:
                    traceback.print_exc()
    
        def date_diff_in_hours(self, epoch_time):
            date = datetime.datetime.utcfromtimestamp(epoch_time)
            diff = datetime.datetime.utcnow() - date
            return diff.seconds / (3600)

    if __name__ == '__main__':
        while True:
            Bot().botcode()