> jupyter nbconvert --to script some_notebook.ipynb 
Traceback (most recent call last):
  File "/usr/local/lib/python3.9/site-packages/traitlets/traitlets.py", line 645, in get
    value = obj._trait_values[self.name]
KeyError: 'template_paths'

During handling of the above exception, another exception occurred:

Traceback (most recent call last):
  File "/usr/local/bin/jupyter-nbconvert", line 33, in <module>
    sys.exit(load_entry_point('nbconvert==7.2.1', 'console_scripts', 'jupyter-nbconvert')())
  File "/usr/local/lib/python3.9/site-packages/jupyter_core/application.py", line 269, in launch_instance
    return super().launch_instance(argv=argv, **kwargs)
  File "/usr/local/lib/python3.9/site-packages/traitlets/config/application.py", line 978, in launch_instance
    app.start()
  File "/usr/local/lib/python3.9/site-packages/nbconvert/nbconvertapp.py", line 426, in start
    self.convert_notebooks()
  File "/usr/local/lib/python3.9/site-packages/nbconvert/nbconvertapp.py", line 594, in convert_notebooks
    cls = get_exporter(self.export_format)
  File "/usr/local/lib/python3.9/site-packages/nbconvert/exporters/base.py", line 106, in get_exporter
    if getattr(exporter(config=config), "enabled", True):
  File "/usr/local/lib/python3.9/site-packages/nbconvert/exporters/templateexporter.py", line 342, in __init__
    super().__init__(config=config, **kw)
  File "/usr/local/lib/python3.9/site-packages/nbconvert/exporters/exporter.py", line 118, in __init__
    self._init_preprocessors()
  File "/usr/local/lib/python3.9/site-packages/nbconvert/exporters/templateexporter.py", line 508, in _init_preprocessors
    conf = self._get_conf()
  File "/usr/local/lib/python3.9/site-packages/nbconvert/exporters/templateexporter.py", line 526, in _get_conf
    for path in map(Path, self.template_paths):
  File "/usr/local/lib/python3.9/site-packages/traitlets/traitlets.py", line 686, in __get__
    return self.get(obj, cls)
  File "/usr/local/lib/python3.9/site-packages/traitlets/traitlets.py", line 648, in get
    default = obj.trait_defaults(self.name)
  File "/usr/local/lib/python3.9/site-packages/traitlets/traitlets.py", line 1752, in trait_defaults
    return self._get_trait_default_generator(names[0])(self)
  File "/usr/local/lib/python3.9/site-packages/traitlets/traitlets.py", line 1132, in __call__
    return self.func(*args, **kwargs)
  File "/usr/local/lib/python3.9/site-packages/nbconvert/exporters/templateexporter.py", line 537, in _template_paths
    template_names = self.get_template_names()
  File "/usr/local/lib/python3.9/site-packages/nbconvert/exporters/templateexporter.py", line 621, in get_template_names
    raise ValueError(
ValueError: No template sub-directory with name 'script' found in the following paths:
	/home/user/.local/share/jupyter
	/usr/local/share/jupyter
	/usr/share/jupyter

The last ipynb to py conversion (--to script) here was done 2022-07-08 so a version after that introduced this bug.