def modify(self, fileobj, events, data=None):
        # TODO: Subclasses can probably optimize this even further.
        try:
            key = self._fd_to_key[self._fileobj_lookup(fileobj)]
        except __HOLE__:
            raise KeyError("{0!r} is not registered".format(fileobj))
        if events != key.events:
            self.unregister(fileobj)
            key = self.register(fileobj, events, data)
        elif data != key.data:
            # Use a shortcut to update the data.
            key = key._replace(data=data)
            self._fd_to_key[key.fd] = key
        return key
dataset/ETHPy150Open dpkp/kafka-python/kafka/selectors34.py/_BaseSelectorImpl.modify