[ISSUE] beets package broken since python upgrade to 3.8.4

[ISSUE] beets package broken since python upgrade to 3.8.4

[thenktor]

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New issue by thenktor on void-packages repository

https://github.com/void-linux/void-packages/issues/23653

Description:
<!-- Don't request update of package. We have a script for that. https://alpha.de.repo.voidlinux.org/void-updates/void-updates.txt . However, a quality pull request may help. -->
### System

* xuname:  Void 5.7.9_1 x86_64 GenuineIntel uptodate rFF
* package:  beets-1.4.9_2
  

### Actual behavior
Same error as described here on Debian bug tracker: https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=964245
Beets needs a bugfix: https://github.com/beetbox/beets/pull/3621

On beet startup this error appears:
```Traceback (most recent call last):
  File "/usr/bin/beet", line 11, in <module>
    load_entry_point('beets==1.4.9', 'console_scripts', 'beet')()
  File "/usr/lib/python3.8/site-packages/beets/ui/__init__.py", line 1266, in main
    _raw_main(args)
  File "/usr/lib/python3.8/site-packages/beets/ui/__init__.py", line 1249, in _raw_main
    subcommands, plugins, lib = _setup(options, lib)
  File "/usr/lib/python3.8/site-packages/beets/ui/__init__.py", line 1144, in _setup
    lib = _open_library(config)
  File "/usr/lib/python3.8/site-packages/beets/ui/__init__.py", line 1201, in _open_library
    get_path_formats(),
  File "/usr/lib/python3.8/site-packages/beets/ui/__init__.py", line 619, in get_path_formats
    path_formats.append((query, template(view.as_str())))
  File "/usr/lib/python3.8/site-packages/beets/util/functemplate.py", line 571, in template
    return Template(fmt)
  File "/usr/lib/python3.8/site-packages/beets/util/functemplate.py", line 581, in __init__
    self.compiled = self.translate()
  File "/usr/lib/python3.8/site-packages/beets/util/functemplate.py", line 614, in translate
    func = compile_func(
  File "/usr/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
```

### Steps to reproduce the behavior
Update python to 3.8.4 and start beets

Re: [ISSUE] [CLOSED] beets package broken since python upgrade to 3.8.4

[sgn]

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Closed issue by thenktor on void-packages repository

https://github.com/void-linux/void-packages/issues/23653

Description:
<!-- Don't request update of package. We have a script for that. https://alpha.de.repo.voidlinux.org/void-updates/void-updates.txt . However, a quality pull request may help. -->
### System

* xuname:  Void 5.7.9_1 x86_64 GenuineIntel uptodate rFF
* package:  beets-1.4.9_2
  

### Actual behavior
Same error as described here on Debian bug tracker: https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=964245
Beets needs a bugfix: https://github.com/beetbox/beets/pull/3621

On beet startup this error appears:
```Traceback (most recent call last):
  File "/usr/bin/beet", line 11, in <module>
    load_entry_point('beets==1.4.9', 'console_scripts', 'beet')()
  File "/usr/lib/python3.8/site-packages/beets/ui/__init__.py", line 1266, in main
    _raw_main(args)
  File "/usr/lib/python3.8/site-packages/beets/ui/__init__.py", line 1249, in _raw_main
    subcommands, plugins, lib = _setup(options, lib)
  File "/usr/lib/python3.8/site-packages/beets/ui/__init__.py", line 1144, in _setup
    lib = _open_library(config)
  File "/usr/lib/python3.8/site-packages/beets/ui/__init__.py", line 1201, in _open_library
    get_path_formats(),
  File "/usr/lib/python3.8/site-packages/beets/ui/__init__.py", line 619, in get_path_formats
    path_formats.append((query, template(view.as_str())))
  File "/usr/lib/python3.8/site-packages/beets/util/functemplate.py", line 571, in template
    return Template(fmt)
  File "/usr/lib/python3.8/site-packages/beets/util/functemplate.py", line 581, in __init__
    self.compiled = self.translate()
  File "/usr/lib/python3.8/site-packages/beets/util/functemplate.py", line 614, in translate
    func = compile_func(
  File "/usr/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
```

### Steps to reproduce the behavior
Update python to 3.8.4 and start beets