keras/src/losses/losses.py/CategoricalFocalCrossentropy/__init__
class CategoricalFocalCrossentropy:    def __init__(
        self,
        alpha=0.25,
        gamma=2.0,
        from_logits=False,
        label_smoothing=0.0,
        axis=-1,
        reduction="sum_over_batch_size",
        name="categorical_focal_crossentropy",
        dtype=None,
    ):
        """Initializes `CategoricalFocalCrossentropy` instance."""
        super().__init__(
            categorical_focal_crossentropy,
            name=name,
            reduction=reduction,
            dtype=dtype,
            alpha=alpha,
            gamma=gamma,
            from_logits=from_logits,
            label_smoothing=label_smoothing,
            axis=axis,
        )
        self.from_logits = from_logits
        self.label_smoothing = label_smoothing
        self.axis = axis
        self.alpha = alpha
        self.gamma = gamma