def _build_subset_state(self, roi):

        if 'make_selector' in self._custom_functions:
            return self.make_selector(roi=roi)
        if 'select' in self._custom_functions:
            return CustomSubsetState(type(self), roi, self.settings())
        raise RuntimeError("Selection not supported for this viewer.")
dataset/ETHPy150Open glue-viz/glue/glue/viewers/custom/qt/custom_viewer.py/CustomViewer._build_subset_state/original