def group_train_data_one_to_one(training_data):
    """
    Group training_data to one-to-one format.
    """
    temp_list = list()
    for p1, p2 in training_data:
        p2_list = list()
        p1 = tuple(p1)
        p2_list.append(p2)
        temp = (p1, p2_list)
        temp_list.append(temp)
    return temp_list