Error messaging if toml file is not well formatted

[chStaiger]

I am creating synthetic data with a toml file. When the toml file is not well formatted metsyn throws this error message:

staig001@busoni autumn-fair % metasyn create-meta  --config event_config.toml
Traceback (most recent call last):
  File "/Users/staig001/.local/bin/metasyn", line 8, in <module>
    sys.exit(main())
             ^^^^^^
  File "/Users/staig001/.local/pipx/venvs/metasyn/lib/python3.12/site-packages/metasyn/__main__.py", line 80, in main
    create_metadata()
  File "/Users/staig001/.local/pipx/venvs/metasyn/lib/python3.12/site-packages/metasyn/__main__.py", line 127, in create_metadata
    meta_frame = MetaFrame.from_config(meta_config)
                 ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/Users/staig001/.local/pipx/venvs/metasyn/lib/python3.12/site-packages/metasyn/metaframe.py", line 169, in from_config
    return cls.fit_dataframe(None, meta_config)
           ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/Users/staig001/.local/pipx/venvs/metasyn/lib/python3.12/site-packages/metasyn/metaframe.py", line 140, in fit_dataframe
    var = MetaVar(
          ^^^^^^^^
  File "/Users/staig001/.local/pipx/venvs/metasyn/lib/python3.12/site-packages/metasyn/var.py", line 72, in __init__
    if self.prop_missing < -1e-8 or self.prop_missing > 1 + 1e-8:
       ^^^^^^^^^^^^^^^^^^^^^^^^^
TypeError: '<' not supported between instances of 'NoneType' and 'float'
staig001@busoni autumn-fair % metasyn create-meta  --config event_config.toml
Traceback (most recent call last):
  File "/Users/staig001/.local/pipx/venvs/metasyn/lib/python3.12/site-packages/metasyn/config.py", line 102, in from_toml
    config_dict = tomllib.load(handle)
                  ^^^^^^^^^^^^^^^^^^^^
  File "/opt/homebrew/Cellar/python@3.12/3.12.4/Frameworks/Python.framework/Versions/3.12/lib/python3.12/tomllib/_parser.py", line 66, in load
    return loads(s, parse_float=parse_float)
           ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/opt/homebrew/Cellar/python@3.12/3.12.4/Frameworks/Python.framework/Versions/3.12/lib/python3.12/tomllib/_parser.py", line 127, in loads
    raise suffixed_err(
tomllib.TOMLDecodeError: Expected newline or end of document after a statement (at line 44, column 8)

The above exception was the direct cause of the following exception:

Traceback (most recent call last):
  File "/Users/staig001/.local/bin/metasyn", line 8, in <module>
    sys.exit(main())
             ^^^^^^
  File "/Users/staig001/.local/pipx/venvs/metasyn/lib/python3.12/site-packages/metasyn/__main__.py", line 80, in main
    create_metadata()
  File "/Users/staig001/.local/pipx/venvs/metasyn/lib/python3.12/site-packages/metasyn/__main__.py", line 120, in create_metadata
    meta_config = MetaConfig.from_toml(args.config)
                  ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/Users/staig001/.local/pipx/venvs/metasyn/lib/python3.12/site-packages/metasyn/config.py", line 109, in from_toml
    raise ValueError(f"It appears '{Path(config_fp).name}' is a"
ValueError: It appears 'event_config.toml' is a '.toml' file. To load a MetaConfig, provide it as a .toml file.

Is it possible to distinguish whether the file was not a toml file or whether it is an incorrectly formatted toml file and adjust the feedback in the error message?