How to use the flake8.options.config.ConfigFileFinder function in flake8

def test_cli_config():
    """Verify opening and reading the file specified via the cli."""
    cli_filepath = CLI_SPECIFIED_FILEPATH
    finder = config.ConfigFileFinder('flake8', None, [])

    parsed_config = finder.cli_config(cli_filepath)
    assert parsed_config.has_section('flake8')

def test_get_local_plugins():
    """Verify get_local_plugins returns expected plugins."""
    config_fixture_path = 'tests/fixtures/config_files/local-plugin.ini'
    config_finder = config.ConfigFileFinder('flake8', [])

    with mock.patch.object(config_finder, 'local_config_files') as localcfs:
        localcfs.return_value = [config_fixture_path]
        local_plugins = config.get_local_plugins(config_finder)

    assert local_plugins.extension == ['XE = test_plugins:ExtensionTestPlugin']
    assert local_plugins.report == ['XR = test_plugins:ReportTestPlugin']

def test_generate_possible_local_files(args, expected):
    """Verify generation of all possible config paths."""
    finder = config.ConfigFileFinder('flake8', args, [])

    assert (list(finder.generate_possible_local_files())
            == expected)

def get_style_guide(**kwargs):
    r"""Provision a StyleGuide for use.

    :param \*\*kwargs:
        Keyword arguments that provide some options for the StyleGuide.
    :returns:
        An initialized StyleGuide
    :rtype:
        :class:`StyleGuide`
    """
    application = app.Application()
    prelim_opts, remaining_args = application.parse_preliminary_options([])
    flake8.configure_logging(prelim_opts.verbose, prelim_opts.output_file)
    config_finder = config.ConfigFileFinder(
        application.program, prelim_opts.append_config
    )

    application.find_plugins(
        config_finder, prelim_opts.config, prelim_opts.isolated
    )
    application.register_plugin_options()
    application.parse_configuration_and_cli(config_finder, remaining_args)
    # We basically want application.initialize to be called but with these
    # options set instead before we make our formatter, notifier, internal
    # style guide and file checker manager.
    options = application.options
    for key, value in kwargs.items():
        try:
            getattr(options, key)
            setattr(options, key, value)