Calling a variadic function with a dictionary should be done with ** to inject the values, but here I use * to inject the keys. It turns out that the order in which the keys are injected is random on Codeskulptor! See my test.
def flip_a_(x, y): return x coin = { "Heads": 0, "Tails": 0, } for n in range(1000): coin[flip_a_(*coin)] += 1 print coin