def _clip_value(self, x_0: np.ndarray) -> np.ndarray:
        """
        Apply clipping to input array

        :param x_0: An array to be clipped
        :return: The array after clipping if clipping is enabled
        """
        if self.enable_clipped:
            x_0 = np.clip(x_0, self.clip_min, self.clip_max)
        return x_0

        Apply clipping to input array

        :param x_0: An array to be clipped
        :return: The array after clipping if clipping is enabled
        
art/attacks/evasion/sign_opt.py