keras/src/layers/regularization/alpha_dropout.py/AlphaDropout/_get_concrete_noise_shape
class AlphaDropout:    def _get_concrete_noise_shape(self, inputs, noise_shape):
        if noise_shape is None:
            return ops.shape(inputs)

        concrete_inputs_shape = ops.shape(inputs)
        concrete_noise_shape = []
        for i, value in enumerate(noise_shape):
            concrete_noise_shape.append(
                concrete_inputs_shape[i] if value is None else value
            )
        return concrete_noise_shape