ptwobrussell/Mining-the-Social-Web-2nd-Edition — pull request #126 by furukama (2014-01-12 21:33:01+00:00)
Title: Getting rid of multiple retweets

For some hashtags, you get 5 identical retweets as there are no other retweets in the search. A set(retweets) could make sense here, because technically, a retweet does not create a new tweet, but just adds a new retweet entity to the original tweet.