in the documentation python sets unordered collection of unique elements python sets set sets Unordered collections of unique elements sets 5.7 sets — Unordered collections of unique elements Set docs https://docs.python.org/2/library/sets.html Python sets Python doc reference set python sets Python sets set() set() sets — Unordered collections of unique elements sets set in the documentation python sets Documentação de set Table of Python Set Operators set methods Python documentation on Set Objects set set methods sets set documentation for sets sets