def METHOD_NAME(df, k, seed, column_name_prefix='ml_phase'):
    kfold = sklearn.model_selection.KFold(n_splits=k, shuffle=True, random_state=seed)
    k=0
    for train_index, test_index in kfold.split(df):
        #print(len(train_index), len(test_index))
        #print(test_index[:20])
        column_name = column_name_prefix + '_fold_' + str(k)
        df[column_name] = ''
        column_index = df.columns.get_loc(column_name)
        #print('COL IND', column_index)
        df.iloc[train_index, column_index] = 'train'
        df.iloc[test_index, column_index] = 'test'
        k += 