Updating to python 3.8.5 breaks beets, was working on 3.8.2

[Extarys]

Problem

Beet was working yesterday. This morning I made some system updates and now beets doesn't work. (Might be another issue than Python though)
Running this command in verbose (-vv) mode:

$ beet -vv ls

Led to this problem:

$ beet -vv ls
user configuration: /home/jer/.config/beets/config.yaml
data directory: /home/jer/.config/beets
plugin paths: 
Sending event: pluginload
lastgenre: Loading canonicalization tree /home/jer/.local/lib/python3.8/site-packages/beetsplug/lastgenre/genres-tree.yaml
Traceback (most recent call last):
  File "/home/jer/.local/bin/beet", line 8, in <module>
    sys.exit(main())
  File "/home/jer/.local/lib/python3.8/site-packages/beets/ui/__init__.py", line 1266, in main
    _raw_main(args)
  File "/home/jer/.local/lib/python3.8/site-packages/beets/ui/__init__.py", line 1249, in _raw_main
    subcommands, plugins, lib = _setup(options, lib)
  File "/home/jer/.local/lib/python3.8/site-packages/beets/ui/__init__.py", line 1144, in _setup
    lib = _open_library(config)
  File "/home/jer/.local/lib/python3.8/site-packages/beets/ui/__init__.py", line 1201, in _open_library
    get_path_formats(),
  File "/home/jer/.local/lib/python3.8/site-packages/beets/ui/__init__.py", line 619, in get_path_formats
    path_formats.append((query, template(view.as_str())))
  File "/home/jer/.local/lib/python3.8/site-packages/beets/util/functemplate.py", line 571, in template
    return Template(fmt)
  File "/home/jer/.local/lib/python3.8/site-packages/beets/util/functemplate.py", line 581, in __init__
    self.compiled = self.translate()
  File "/home/jer/.local/lib/python3.8/site-packages/beets/util/functemplate.py", line 614, in translate
    func = compile_func(
  File "/home/jer/.local/lib/python3.8/site-packages/beets/util/functemplate.py", line 155, in compile_func
    prog = compile(mod, '<generated>', 'exec')
ValueError: Name node can't be used with 'None' constant
Error in sys.excepthook:
Traceback (most recent call last):
  File "/usr/lib/python3/dist-packages/apport_python_hook.py", line 76, in apport_excepthook
    binary = os.path.realpath(os.path.join(os.getcwd(), sys.argv[0]))
FileNotFoundError: [Errno 2] No such file or directory

Original exception was:
Traceback (most recent call last):
  File "/home/jer/.local/bin/beet", line 8, in <module>
    sys.exit(main())
  File "/home/jer/.local/lib/python3.8/site-packages/beets/ui/__init__.py", line 1266, in main
    _raw_main(args)
  File "/home/jer/.local/lib/python3.8/site-packages/beets/ui/__init__.py", line 1249, in _raw_main
    subcommands, plugins, lib = _setup(options, lib)
  File "/home/jer/.local/lib/python3.8/site-packages/beets/ui/__init__.py", line 1144, in _setup
    lib = _open_library(config)
  File "/home/jer/.local/lib/python3.8/site-packages/beets/ui/__init__.py", line 1201, in _open_library
    get_path_formats(),
  File "/home/jer/.local/lib/python3.8/site-packages/beets/ui/__init__.py", line 619, in get_path_formats
    path_formats.append((query, template(view.as_str())))
  File "/home/jer/.local/lib/python3.8/site-packages/beets/util/functemplate.py", line 571, in template
    return Template(fmt)
  File "/home/jer/.local/lib/python3.8/site-packages/beets/util/functemplate.py", line 581, in __init__
    self.compiled = self.translate()
  File "/home/jer/.local/lib/python3.8/site-packages/beets/util/functemplate.py", line 614, in translate
    func = compile_func(
  File "/home/jer/.local/lib/python3.8/site-packages/beets/util/functemplate.py", line 155, in compile_func
    prog = compile(mod, '<generated>', 'exec')
ValueError: Name node can't be used with 'None' constant

Setup

• OS: Linux Linux Mint 20 Cinnamon 5.4.0-48-generic
• Python version: 3.8
• beets version: unknown, latest as of last week
• Turning off plugins made problem go away (yes/no): No

My configuration (output of beet config) is:
Command gives an error. But here is my config, I commented a lot of lines to try and find if the config was the problem, doesn't appear to be.

directory: /media/NAS/Music
library: /media/hdd/.beet_library.blb
#logs: /media/hdd/opt/beet/library.log


original_date: no
per_disc_numbering: yes
threaded: yes
#clutter: ["Thumbs.DB", ".DS_Store", "*.m3u", ".pls"]
#ignore: ["*~", "System Volume Information"]

import:
    languages: en de fr jp
    move: yes
    copy: no
    bell: yes

ui:
    color: yes
    colors:
        text_success: green
        text_warning: yellow
        text_error: red
        text_highlight: red
        text_highlight_minor: lightgray
        action_default: turquoise
        action: cyan

plugins: inline convert bpm discogs lastgenre acousticbrainz scrub fromfilename chroma acousticbrainz beatport the ftintitle fetchart embedart

aunique:
    keys: albumartist album
    disambiguators: albumtype year label catalognum albumdisambig releasegroupdisambig
    bracket: '()'

set_fields:
    how: ''

# item_fields:
#     my_samplerate: str(round(samplerate / 1000))
#     my_bitrate: str(round(bitrate/1000))
#     is_flac: 1 if format == "FLAC" else 0
#     is_album: 1 if albumtype.upper() == "ALBUM" else 0
#     multidisc: 1 if disctotal > 1 else 0
#     vinyl: 1 if media in ['12" Vinyl', 'Vinyl'] else 0
#     compilation_display: '''Soundtracks'' if albumtype.upper() == ''SOUNDTRACK'' else ''Compilations'''
#     #first_artist: albumartist.split(', ',1)[0:1][0]

# album_fields:  
#     fileformat: |
#         formatList = []
#         for item in items:
#             formatList.append(item.format.upper())
#         return formatList
#     av_bitrate: |
#         total = 0
#         for item in items:
#             total += item.bitrate
#         return str(round(total / len(items) / 1000))
#     avg_samplerate: |
#         total = 0
#         for item in items:
#             total += item.samplerate
#         return str(round(total / len(items) / 1000))
#     avg_bitdepth: |
#         total = 0
#         for item in items:
#             total += item.bitdepth
#         return str(round(total / len(items)))

paths:
    #default: %upper{%left{%asciify{%the{$albumartist}},1}}/$albumartist/%if{$year,$year - ,%if{$original_year,$original_year - }}$album%aunique{} ($format)/%if{$multidisc,$disc-}$track - $title
    # Albums/A/ASCI Artist Name, The/[YEAR] ASCI Album Name, The [EP]/01 - Track Name.mp3
    # %bucket{%upper{%left{%the{$albumartist},1}}}/
    default: $title
    #default: '%the{$albumartist}/%if{$original_year,$original_year,0000} - $album%aunique{albumartist album year catalognum, catalognum albumtype label albumdisambig} [%ifdef{how,$how }%upper{$format}%if{$is_flac, $avg_samplerate-$avg_bitdepth, $av_bitrate}]/%if{$multidisc,$disc-}$track - $title'
    #albumtype:single: '%the{$albumartist}/Singles/%if{$original_year,$original_year,0000} - $album%aunique{albumartist album year catalognum, catalognum albumtype label albumdisambig} [%ifdef{how,$how }%upper{$format}%if{$is_flac, $avg_samplerate-$avg_bitdepth, $av_bitrate}]/%if{$multidisc,$disc-}$track - $title'
    #albumtype:ep: '%the{$albumartist}/EPs/%if{$original_year,$original_year,0000} - $album%aunique{albumartist album year catalognum, catalognum albumtype label albumdisambig} [%ifdef{how,$how }%upper{$format}%if{$is_flac, $avg_samplerate-$avg_bitdepth, $av_bitrate}]/%if{$multidisc,$disc-}$track - $title'
    #albumtype:soundtrack: Soundtracks/%if{$year,$year - ,%if{$original_year,$original_year - }}$album%aunique{} [%ifdef{how,$how }%upper{$format}%if{$is_flac, $avg_samplerate-$avg_bitdepth, $av_bitrate}]/%if{$vinyl,$track_alt,%if{$multidisc,$disc-}$track} - $title
    #comp: $compilation_display/%if{$year,$year - ,%if{$original_year,$original_year - }}$album%aunique{} [%ifdef{how,$how }%upper{$format}%if{$is_flac, $avg_samplerate-$avg_bitdepth, $av_bitrate}]/%if{$multidisc,$disc-}$track - $title
    #singleton: '%the{$artist}/Non-Album/$title%if{$original_year, ($original_year),%if{$year, ($year),}} [%ifdef{how,$how }%upper{$format}%if{$is_flac, $samplerate-$bitdepth, $my_bitrate}]'

replace:
    '[\\/]': _
    '^\.': _
    '[\x00-\x1f]': _
    '[<>:"\?\*\|]': _
    '\.$': _
    '\s+$': ''
    '^\s+': ''
    '^-': _
    '[\u2018\u2019]': ''''
    '[\u201c\u201d\u2033]': '"'

check:
    import: yes
    write-check: yes
    write-update: yes
    convert-update: yes
    threads: 4

ftintitle:
    auto: yes
    drop: no
    format: feat. {0}

lyrics:
  fallback: ''
  google_engine_ID: xxxxxxx
  google_API_key: xxxxxxx

lastgenre:
    min_weight: 80
    count: 5
    prefer_specific: yes
    separator: '; '

extrafiles:
    patterns:
        artworkdir:
          - '[sS]cans/'
          - '[aA]rtwork/'
        #lyrics:
        #  - '*.lrc'
        nfo:
          - 'album.nfo'
    paths:
        artworkdir: $albumpath/artwork
        #lyrics: $albumpath/$filename.lrc

embedart:
    # I dont want album art auto-embedded either
    auto: no

fetchart:
  auto: yes
  minwidth: 400
  maxwidth: 1600
  sources: filesystem coverart itunes amazon albumart

acousticbrainz:
    force: yes

acoustid:
    apikey: xxxxxxx

[jackwilsdon]

This has been fixed on master but we haven't pushed a release containing the fix yet. See #3674.

[Extarys]

@jackwilsdon Oh I'm sorry! Thanks!

I'll follow the instructions here: https://beets.readthedocs.io/en/latest/faq.html#run-the-latest-source-version-of-beets