AssertionError: '/' not in parts when i create a folder myself

[AbdealiLoKo]

I moved all the logs from ~/.travis/AbdealiJK/pywikibot-core to ~/.travis/AbdealiJK/pywikibot-core/older to clean it up and reduce the number of files in there. And got the error:

Traceback (most recent call last):
  File "/home/ajk/Documents/wiki/venv3/bin/travis_log_fetch", line 11, in <module>
    sys.exit(main())
  File "/home/ajk/Documents/wiki/venv3/lib/python3.4/site-packages/travis_log_fetch/cmdline.py", line 94, in main
    targets = skip_stored(targets, options.dir, options.format)
  File "/home/ajk/Documents/wiki/venv3/lib/python3.4/site-packages/travis_log_fetch/_store.py", line 106, in skip_stored
    stored_targets = get_stored_targets(base_dir, log_filename_format)
  File "/home/ajk/Documents/wiki/venv3/lib/python3.4/site-packages/travis_log_fetch/_store.py", line 69, in get_stored_targets
    target.slug = parsed_filename['job.repository.slug']
  File "/home/ajk/Documents/wiki/venv3/lib/python3.4/site-packages/travis_log_fetch/_target.py", line 58, in slug
    assert '/' not in parts[1]
AssertionError

When I moved the folder older to another place this error stopped occurring and it worked fine.