def METHOD_NAME(rule_obj, lang, products):
    if not products or len(products) != 2 or products[0] == products[1]:
        raise ValueError("Must pass exactly two products for the diff option.")
    if 'remediations' not in rule_obj or lang not in rule_obj['remediations']:
        raise ValueError("Rule is missing fixes.")
    left_fix_file = ssg.fixes.get_fix_path(rule_obj, lang, products[0])
    right_fix_file = ssg.fixes.get_fix_path(rule_obj, lang, products[1])
    subprocess.run(['diff', '--color=always', left_fix_file, right_fix_file])