from snanosm.mealy import Machine

def add_to_result(context, c):
    context["result"] += c

def inverter(input_string: str) -> str:
    context = {
        "result": ""
    }
    m = Machine(context)
    m.add_state("S", True, False)
    m.add_transition("0", "S", "S", lambda ctx: add_to_result(ctx, "1"))
    m.add_transition("1", "S", "S", lambda ctx: add_to_result(ctx, "0"))
    for c in input_string:
        m.process_input(c)
    return context["result"]

if __name__ == '__main__':
    print(inverter("000011110010"))