def _remove_io_handler(self, handler):
if handler in self._unprepared_handlers:<EOL><INDENT>old_fileno = self._unprepared_handlers[handler]<EOL>del self._unprepared_handlers[handler]<EOL><DEDENT>else:<EOL><INDENT>old_fileno = handler.fileno()<EOL><DEDENT>if old_fileno is not None:<EOL><INDENT>del self._handlers[old_fileno]<EOL>self.io_loop.remove_handler(handler.fileno())<EOL><DEDENT>
Remove an i/o-handler.