def METHOD_NAME(y: np.ndarray, y_pred: np.ndarray) -> float:
    """An error metric in case y, y_pred are images.
    Defined as 1 - the maximal F-score of pixel similarity, or squared
    Euclidean distance between the original and the result labels.
    Parameters
    ----------
    y: np.ndarray
        ground truth array
    y_pred: np.ndarray
        predicted array
    Returns
    -------
    score: float
        The pixel-error. A number between 0 and 1.
    """
    return 1 - f1_score(y, y_pred)