I\'ve recently noticed something interesting when looking at Python 3.3 grammar specification:
funcdef: \'def\' NAME parameters [\'->\' test] \':\' suite
def function(arg)->123:
It's simply a return type, integer in this case doesn't matter which number you write.
like Java :
public int function(int args){...}
But for Python (how Jim Fasarakis Hilliard said) the return type it's just an hint, so it's suggest the return but allow anyway to return other type like a string..