code: def _handle_event(self, handler, fd, event):
          
          # pylint: disable=C0103
          logger.debug('_handle_event: %r, %r, %r', handler, fd, event)
          if event & ioloop.IOLoop.ERROR:
              handler.handle_hup()
          if event & ioloop.IOLoop.READ:
              handler.handle_read()
          if event & ioloop.IOLoop.WRITE:
              handler.handle_write()
          self._configure_io_handler(handler)
docs: handle I/O events