Tuples & sets

Tuples are fixed, ordered groups (great for returning several values); sets are unordered collections of unique items.

A tuple uses `( )` and can’t be changed; you can unpack it: `x, y = point`. A set uses `{ }` and automatically drops duplicates. `in` tests membership quickly.

point = (3, 4)
x, y = point          # unpack
unique = {1, 2, 2, 3} # {1, 2, 3}