keras/src/layers/activations/relu.py/ReLU/__init__
class ReLU:    def __init__(
        self, max_value=None, negative_slope=0.0, threshold=0.0, **kwargs
    ):
        super().__init__(**kwargs)
        if max_value is not None and max_value < 0.0:
            raise ValueError(
                "max_value of a ReLU layer cannot be a negative "
                f"value. Received: max_value={max_value}"
            )
        if negative_slope is None or negative_slope < 0.0:
            raise ValueError(
                "negative_slope of a ReLU layer cannot be a negative "
                f"value. Received: negative_slope={negative_slope}"
            )
        if threshold is None or threshold < 0.0:
            raise ValueError(
                "threshold of a ReLU layer cannot be a negative "
                f"value. Received: threshold={threshold}"
            )

        self.supports_masking = True
        self.max_value = max_value
        self.negative_slope = negative_slope
        self.threshold = threshold