def PreStem(name=None):
    """Normalizes inputs with ImageNet-1k mean and std."""
    if name is None:
        name = "prestem" + str(backend.get_uid("prestem"))

    def apply(x):
        x = layers.Normalization(
            mean=[0.485 * 255, 0.456 * 255, 0.406 * 255],
            variance=[
                (0.229 * 255) ** 2,
                (0.224 * 255) ** 2,
                (0.225 * 255) ** 2,
            ],
            name=name + "_prestem_normalization",
        )(x)
        return x

    return apply
Normalizes inputs with ImageNet-1k mean and std.
keras/src/applications/convnext.py