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Solve the following problem using Python, implementing the functions described below, one line at a time
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Description:
 def add_callback(self, fn, *args, **kwargs):
 """Pass a function to be called when IO is complete."""

        if _debug: IOCB._debug("add_callback(%d) %r %r %r", self.ioID, fn, args, kwargs)

        # store it
        self.ioCallback.append((fn, args, kwargs))

        # already complete?
        if self.ioComplete.isSet():
            self.trigger()