def modify_state_for_body(s, body):
            s.layers['segmentation'].segments = frozenset([body.segment_id])
            s.voxel_coordinates = body.bbox_start + body.bbox_size // 2
def __add__(self, other):
        assert self.n_classes == other.n_classes, "Number of classes does not match"
        return MulticlassContingencyTable(self.table + other.table,
                                          n_classes=self.n_classes,
                                          class_names=self.class_names)