Mutagen header only with FLAC and ID3

[Drew Abbott]

I am trying to save only the metadata blocks of a file generated with mutagen using something like this:

from mutagen.flac import FLAC

from io import BytesIO

foo = FLAC()

foo.add_tags() # AttributeError: 'FLAC' object has no attribute 'metadata_blocks'

foo.add_tags() # mutagen.flac.FLACVorbisError: a Vorbis comment already exists

foo['artist'] = 'test'

bio = BytesIO()

foo.save(bio) # AttributeError: 'FLAC' object has no attribute 'metadata_blocks'

is it possible to write FLAC metadata blocks without audio frame data or otherwise frame data of negligible size? If so, is it also possible to do this with ID3 data?