Issue

I was working on the project and found a small issue in the hyperparameter file. The function `render_cv_scheme()` crashes because it uses a hardcoded group (1, 111) which may not exist in all datasets.

Suggested correction:

random_time_series = next(
    group.reset_index(level=[0, 1], drop=True)
    for _, group in y_train.groupby(level=[0, 1])
    if len(group) >= cv.fh[-1] * 3
)
