@property
    def slice_ind(self):
        """
        For 3D data, returns the pixel index of the current slice.
        Otherwise, returns `None`.
        """
        if self.is_3D:
            for s in self.slice:
                if s not in ['x', 'y']:
                    return s
        return None
dataset/ETHPy150Open glue-viz/glue/glue/viewers/image/client.py/ImageClient.slice_ind/original