tvnamer: After python3.8 update I receive error

Hi, I recently installed the latest python3.8 update (3.8.13) via pkg (FreeBSD).

Now I receive the following error with tvnamer:

#tvnamer .

Traceback (most recent call last):
  File "/usr/local/bin/tvnamer", line 33, in <module>
    sys.exit(load_entry_point('tvnamer==3.0.4', 'console_scripts', 'tvnamer')())
  File "/usr/local/bin/tvnamer", line 25, in importlib_load_entry_point
    return next(matches).load()
  File "/usr/local/lib/python3.8/importlib/metadata.py", line 77, in load
    module = import_module(match.group('module'))
  File "/usr/local/lib/python3.8/importlib/__init__.py", line 127, in import_module
    return _bootstrap._gcd_import(name[level:], package, level)
  File "<frozen importlib._bootstrap>", line 1014, in _gcd_import
  File "<frozen importlib._bootstrap>", line 991, in _find_and_load
  File "<frozen importlib._bootstrap>", line 975, in _find_and_load_unlocked
  File "<frozen importlib._bootstrap>", line 671, in _load_unlocked
  File "<frozen importlib._bootstrap_external>", line 843, in exec_module
  File "<frozen importlib._bootstrap>", line 219, in _call_with_frames_removed
  File "/usr/local/lib/python3.8/site-packages/tvnamer/main.py", line 18, in <module>
    import tvdb_api
  File "/usr/local/lib/python3.8/site-packages/tvdb_api.py", line 34, in <module>
    from requests_cache.backends.base import _to_bytes, _DEFAULT_HEADERS
ImportError: cannot import name '_to_bytes' from 'requests_cache.backends.base' (/usr/local/lib/python3.8/site-packages/requests_cache/backends/base.py)

Unfortunately I am a Python illiterate. Is this a problem with tvnamer?

Many thanks

Georg