def accuracy_score_(y_true, y_pred):
    """
    Compute the accuracy score.
    Args:
        y_true: a scalar or a numpy array for the correct labels.
        y_pred: a scalar or a numpy array for the predicted labels.
    Returns:
        The accuracy score as a float.
        None on any error.
    Raises:
        This function should not raise any Exception.
    """
    try:
        if y_true.size != y_pred.size:
            return None
        return (y_true == y_pred).mean()
    except Exception:
        return None