code: def features(filename='tweets.zip'):
      
      raise NotImplemented("Need to implement feature extraction.")
      js = load_tweets(filename)
      index = []
      table = []
      columns = [u'text', u'is_quote_status',
                 u'in_reply_to_status_id', u'in_reply_to_user_id',
                 u'favorited', u'favorite_count',  u'retweeted', u'retweet_count',
                 u'source', u'coordinates',
                 (u'user', u'id'), (u'user', u'followers_count'), (u'user', u'location'),
                 (u'metadata', u'iso_language_code'),
                 u'user',
                 u'geo',
                 u'in_reply_to_user_id_str',
                 u'possibly_sensitive',
                 u'lang',
                 u'created_at',
                 u'in_reply_to_status_id_str',
                 u'place',
                 ]
  
      for tweet in js:
          index += [int(tweet['id'])]
          txt += [tweet['text']]
docs: NotImplemented