keras/src/losses/losses.py/MeanAbsolutePercentageError/__init__
class MeanAbsolutePercentageError:    def __init__(
        self,
        reduction="sum_over_batch_size",
        name="mean_absolute_percentage_error",
        dtype=None,
    ):
        super().__init__(
            mean_absolute_percentage_error,
            name=name,
            reduction=reduction,
            dtype=dtype,
        )