Why?

D:\lsun-master>python ./data.py export 0
Exporting 0 to
Traceback (most recent call last):
  File "./data.py", line 87, in <module>
    main()
  File "./data.py", line 83, in main
    export_images(lmdb_path, args.out_dir, args.flat)
  File "./data.py", line 42, in export_images
    image_out_dir = join(out_dir, '/'.join(key[:6]))
TypeError: sequence item 0: expected str instance, int found