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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 _on_io_events(self, fd=None, _events=None):
 """Invoked by Tornado's IOLoop when there are events for the fd :param int fd: The file descriptor for the event :param int _events: The events raised """

        if fd not in self._connections:
            LOGGER.warning('Received IO event for non-existing connection')
            return
        self._poll_connection(fd)