function is an object
>>> def a(): print 'a'; >>> def b(): print 'b'; >>> def c(): print 'c'; >>> list = [a,b,c]; >>> for f in list: f(); a b c
>>> def a(): print 'a'; >>> def b(): print 'b'; >>> def c(): print 'c'; >>> list = [a,b,c]; >>> for f in list: f(); a b c