set Python sets sets http://docs.python.org/2/library/sets.html http://docs.python.org/2/library/sets.html Python sets Python documentation on Set Objects Set http://docs.python.org/2/library/sets.html (cf. python doc) http://docs.python.org/2/library/sets.html deprecated requires both arguments to be sets docs.python.org/2/library/sets.html set Python sets see http://docs.python.org/2/library/sets.html Python sets Python sets http://docs.python.org/2/library/sets.html sets set straightforward