Error when no base-dir is provided

[knods3k]

Describe the bug
When no base-dir is provided, the program is interrupted due to a Python error.

To Reproduce
bandcamp-dl -fegr your-album-url-here

Expected behavior
The program should download the album from the URL.

Logs

Traceback (most recent call last):
  File "/opt/homebrew/bin/bandcamp-dl", line 8, in <module>
    sys.exit(main())
             ~~~~^^
  File "/opt/homebrew/Cellar/bandcamp-dl/0.0.16_1/libexec/lib/python3.13/site-packages/bandcamp_dl/__main__.py", line 132, in main
    bandcamp_downloader.start(album)
    ~~~~~~~~~~~~~~~~~~~~~~~~~^^^^^^^
  File "/opt/homebrew/Cellar/bandcamp-dl/0.0.16_1/libexec/lib/python3.13/site-packages/bandcamp_dl/bandcampdownloader.py", line 52, in start
    self.download_album(album)
    ~~~~~~~~~~~~~~~~~~~^^^^^^^
  File "/opt/homebrew/Cellar/bandcamp-dl/0.0.16_1/libexec/lib/python3.13/site-packages/bandcamp_dl/bandcampdownloader.py", line 229, in download_album
    os.remove(self.album_art)
              ^^^^^^^^^^^^^^
AttributeError: 'BandcampDownloader' object has no attribute 'album_art'

Desktop (please complete the following information):

• OS: macOS
• Version Sequaia 15.2
• Python Version 3.12.8

Additional context
Works as expected when base-dir is provided.