Python tuple() built-in function

From the Python 3 documentation Rather than being a function, tuple is actually an immutable sequence type, as documented in Tuples and Sequence Types — list, tuple, range.

Examples

>>> t = tuple()
>>> type(t)
# <class 'tuple'>
>>> t
# ()

>>> l = [1, 2, 3]
>>> tuple(l)
# (1, 2, 3)