function annotations

Python 3.1.3 (r313:86834, Nov 28 2010, 11:28:10)
[GCC 4.4.5] on linux2
Type "help", "copyright", "credits" or "license" for more information.
>>> def foo(x: "First operand", y: "Second operand") -> "Sum of operand squares":
...     return x * x + y * y
...
>>> foo(3, 4)
25
>>> print(foo.__annotations__)
{'y': 'Second operand', 'x': 'First operand', 'return': 'Sum of operand squares'}