def make_dict_both_case(dictionary):
    """Make dictionary contain letters of both cases"""
    combined_case_dict = {
        k.lower(): set(l.lower() for l in v) | set(l.upper() for l in v)
        for k, v in dictionary.items()
    }
    both_case_dict = combined_case_dict.copy()
    for key, value in combined_case_dict.items():
        both_case_dict[key.upper()] = value
    return both_case_dict