python-cmd2 fails to build with Python 3.15.0a8.

Various AssertionErrors appear in the tests, examples (and more - 32 failing tests):

_________________________ test_argparse_help_docstring _________________________

argparse_app = <tests.test_argparse.ArgparseApp object at 0x7f2aac82ec10>

    def test_argparse_help_docstring(argparse_app) -> None:
        out, _err = run_cmd(argparse_app, 'help say')
>       assert out[0].startswith('Usage: say')
               ^^^^^^
E       IndexError: list index out of range

_____________________ test_apcustom_nargs_range_validation _____________________

cust_app = <tests.test_argparse_custom.ApCustomTestApp object at 0x7f2aacea91d0>

    def test_apcustom_nargs_range_validation(cust_app) -> None:
        # nargs = (3,)  # noqa: ERA001
        _out, err = run_cmd(cust_app, 'range --arg2 one two')
>       assert 'Error: argument --arg2: expected at least 3 arguments' in err[2]
E       AssertionError: assert 'Error: argument --arg2: expected at least 3 arguments' in ''

_________________________ test_help_with_no_docstring __________________________

capsys = <_pytest.capture.CaptureFixture object at 0x7f2aad643950>

    def test_help_with_no_docstring(capsys) -> None:
        app = HelpNoDocstringApp()
        app.onecmd_plus_hooks('greet -h')
        out, err = capsys.readouterr()
>       assert err == ''
E       AssertionError: assert 'TypeError: C...ebug true\n\n' == ''
E         
E         + TypeError: Cmd2ArgumentParser._get_formatter() got an unexpected keyword 
E         + argument 'file'
E         + 
E         + To enable full traceback, run the following command: set debug true
E         +

https://docs.python.org/3.15/whatsnew/3.15.html

For the build logs, see:
https://copr-be.cloud.fedoraproject.org/results/@python/python3.15/fedora-rawhide-x86_64/10398220-python-cmd2/

For all our attempts to build python-cmd2 with Python 3.15, see:
https://copr.fedorainfracloud.org/coprs/g/python/python3.15/package/python-cmd2/

Testing and mass rebuild of packages is happening in copr.
You can follow these instructions to test locally in mock if your package builds with Python 3.15:
https://copr.fedorainfracloud.org/coprs/g/python/python3.15/

Let us know here if you have any questions.

Python 3.15 is planned to be included in Fedora 45.
To make that update smoother, we're building Fedora packages with all pre-releases of Python 3.15.
A build failure prevents us from testing all dependent packages (transitive [Build]Requires),
so if this package is required a lot, it's important for us to get it fixed soon.

We'd appreciate help from the people who know this package best,
but if you don't want to work on this now, let us know so we can try to work around it on our side.