keras/src/layers/core/lambda_layer.py/Lambda/call
class Lambda:    def call(self, inputs, mask=None, training=None):
        # We must copy for thread safety,
        # but it only needs to be a shallow copy.
        kwargs = {k: v for k, v in self.arguments.items()}
        if self._fn_expects_mask_arg:
            kwargs["mask"] = mask
        if self._fn_expects_training_arg:
            kwargs["training"] = training
        return self.function(inputs, **kwargs)