def _sfn(l, mask, myrad, bcast_var):
    """Score classifier on searchlight data using cross-validation.

    The classifier is in `bcast_var[2]`. The labels are in `bast_var[0]`. The
    number of cross-validation folds is in `bast_var[1].
    """
    clf = bcast_var[2]
    data = l[0][mask, :].T
    # print(l[0].shape, mask.shape, data.shape)
    skf = model_selection.StratifiedKFold(n_splits=bcast_var[1],
                                          shuffle=False)
    accuracy = np.mean(model_selection.cross_val_score(clf, data,
                                                       y=bcast_var[0],
                                                       cv=skf,
                                                       n_jobs=1))
    return accuracy
Score classifier on searchlight data using cross-validation.

    The classifier is in `bcast_var[2]`. The labels are in `bast_var[0]`. The
    number of cross-validation folds is in `bast_var[1].