def predict_row(row, clf):
    """
    Transform row to a 1-row pandas.DataFrame and predict

    When iterating of rows of a DataFrame, each row is represented as a
    pd.Series. The classifiers in use are expecting a DataFrame. This function
    turns the row into a 1 x n_featurs DataFrame and apply the prediction of a
    trained classier.

    Parameters
    ----------
    row : pandas.Series
        An instance from the data.
    clf
        Predictor which expects the features which are the index of ``row``
        and is already trained

    Returns
    -------
    int
        Value of the prediction
    """

    return clf.predict(
        pd.DataFrame(row).T
    )[0]