code: def _remove_io_handler(self, handler):
          
          if handler in self._unprepared_handlers:
              del self._unprepared_handlers[handler]
          tag = self._prepare_sources.pop(handler, None)
          if tag is not None:
              glib.source_remove(tag)
          tag = self._io_sources.pop(handler, None)
          if tag is not None:
              glib.source_remove(tag)
docs: Remove an i/o-handler.