Tuples are sequences that contain arbitrary Python objects.
The items of a tuple are arbitrary Python objects. Tuples of two
or more items are formed by comma-separated lists of expressions. A
tuple of one item (a singleton
) can be formed by affixing a
comma to an expression (an expression by itself does not create a
tuple, since parentheses must be usable for grouping of
expressions). An empty tuple can be formed by an empty pair of
parentheses.