def METHOD_NAME(self, **kwargs):
    if isinstance(self.layer, GeoJson):
        keys = tuple(self.layer.data["features"][0]["properties"].keys())
    elif isinstance(self.layer, TopoJson):
        obj_name = self.layer.object_path.split(".")[-1]
        keys = tuple(
            self.layer.data["objects"][obj_name]["geometries"][0][
                "properties"
            ].keys()
        )  # noqa
    else:
        keys = None
    self.test_params(keys=keys)
    super().METHOD_NAME(**kwargs)