Add the specified members to the set stored at key. Specified members that are already a member of this set are ignored.
If key does not exist, a new set is created before adding the specified members.
Jan Krüger, Sönke Ludwig, Michael Eisendle, Etienne Cimon
© 2012-2016 RejectedSoftware e.K.
Subject to the terms of the MIT license, as written in the included LICENSE.txt file.