Ranker error

[gogasca]

[2019-11-25 06:01:01,697: ERROR/MainProcess] Task rank_news[6394a707-d8dc-4d26-94ac-21111cb68763] raised unexpected: TypeError("'<' not supported between instances of 'list' and 'int'",)
Traceback (most recent call last):
  File "/usr/local/lib/python3.6/site-packages/celery/app/trace.py", line 240, in trace_task
    R = retval = fun(*args, **kwargs)
  File "/usr/local/lib/python3.6/site-packages/celery/app/trace.py", line 438, in __protected_call__
    return self.run(*args, **kwargs)
  File "/usr/local/src/news_ml/main/appD.py", line 89, in rank_news
    ranker_instance.rank_articles()
  File "/usr/local/src/news_ml/services/ranking/RankerD.py", line 107, in rank_articles
    self.sorted_articles = sort_articles(self.articles)
  File "/usr/local/src/news_ml/services/ranking/ranker.py", line 185, in sort_articles
    if articles < 1:
TypeError: '<' not supported between instances of 'list' and 'int'