class Karl:
    "some class for testing concepts and syntax"
    a = []
    def __setitem__(self, a, aa): 
        a = aa
        print " ".join(["setitem", str(a), "=", str(aa)])
    def __getitem__(self, a): 
        print " ".join(["getitem", str(a)])
        return a


interaction:

>>> import test3
>>> hej = test3.Karl()
>>> hej[""]
getitem 
''
>>> hej[""] = [1,2]
setitem [1, 2] = [1, 2]
>>> hej[""]
getitem 
''