guides/training_with_built_in_methods.py/LogisticEndpoint/call
class LogisticEndpoint:    def call(self, targets, logits, sample_weights=None):
        # Compute the training-time loss value and add it
        # to the layer using `self.add_loss()`.
        loss = self.loss_fn(targets, logits, sample_weights)
        self.add_loss(loss)

        # Return the inference-time prediction tensor (for `.predict()`).
        return ops.softmax(logits)