Merge "Allow empty preuload_files." into main

    parser = argparse.ArgumentParser(

            description='Generate Java and C++ enums based on annotations in VehicleProperty.aidl')

    parser.add_argument('--android_build_top', required=False, help='Path to ANDROID_BUILD_TOP')

    parser.add_argument('--preupload_files', nargs='+', required=False, help='modified files')

    parser.add_argument('--preupload_files', nargs='*', required=False, help='modified files')

    parser.add_argument('--check_only', required=False, action='store_true',

            help='only check whether the generated files need update')

    parser.add_argument('--output_csv', required=False,