import os
import signal

class Bug:
    def run(self):
        pid = os.getpid()
        SIGNUM = signal.SIGINT

        for loop in range(16):
            print("LOOP", loop)
            self.called = False
            def handler(func_signum, frame):
                self.called = True

            old_signal = signal.signal(SIGNUM, handler)
            try:
                os.kill(pid, SIGNUM)
                if not self.called:
                    raise Exception("bug")
            finally:
                signal.signal(SIGNUM, old_signal )

if __name__ == "__main__":
    Bug().run()