Qu'affiche le code Python suivant ?

def cc(*cmds):
    stack = []
    outputs = []
    for c in cmds:
        match c:
            case ("push", x):
                stack.append(x)
            case ("pop",):
                if stack:
                    outputs.append(stack.pop())
            case ("sum",):
                if len(stack) >= 2:
                    a = stack.pop()
                    b = stack.pop()
                    stack.append(a + b)
            case _:
                pass
    return outputs
print(cc(("push", 1), ("pop",), ("pop",)),
      cc(("push", 1), ("push", -1), ("sum",), ("pop",)),
      cc(("pop",),))