keras/src/metrics/iou_metrics.py/MeanIoU/__init__
class MeanIoU:    def __init__(
        self,
        num_classes,
        name=None,
        dtype=None,
        ignore_class=None,
        sparse_y_true=True,
        sparse_y_pred=True,
        axis=-1,
    ):
        target_class_ids = list(range(num_classes))
        super().__init__(
            name=name,
            num_classes=num_classes,
            target_class_ids=target_class_ids,
            axis=axis,
            dtype=dtype,
            ignore_class=ignore_class,
            sparse_y_true=sparse_y_true,
            sparse_y_pred=sparse_y_pred,
        )