get_parse needs to explore subclasses recusively
Without:
$ python3 main.py --show tests/data/dirty.mp3 [-] tests/data/dirty.mp3's format (audio/mpeg) is not supported
With:
$ python3 main.py --show tests/data/dirty.mp3 [+] Metadata for tests/data/dirty.mp3: TIT2: ['I am so'] TALB: ['harmfull'] TXXX:I am a : ['various comment'] TDRC: ['1337'] COMM::