def _filter_y_pred(y_pred, conf_threshold):
    """
    Given a list of list of predicted craters return those
    with a confidence value above given threshold

    Parameters
    ----------
    y_pred : list of list of tuples
    conf_threshold : float

    Returns
    -------
    y_pred_filtered : list of list of tuples

    """
    return [[detected_object[1:]
             for detected_object in y_pred_patch
             if detected_object[0] > conf_threshold]
            for y_pred_patch in y_pred]