def best_values(series, nb=None, min_count=None):
    """Return unique values in series ordered by most to less occurrences"""
    occurrences = series.value_counts()
    if min_count:
        occurrences = occurrences[occurrences > min_count]
    nb = len(occurrences) if nb is None else nb
    return list(occurrences.index[:nb])