def group_slice(self):
        """The current group slice of the view, or None if the view is not
        grouped.
        """
        if not self._has_slices:
            return None

        if self.__group_slice is not None:
            return self.__group_slice or None

        return self._dataset.group_slice
The current group slice of the view, or None if the view is not
        grouped.
        
fiftyone/core/view.py