How to use the pycodestyle.get_parser function in pycodestyle

def test_linter():
    argv = ['--application-import-names=flake8_import_order']
    parser = pycodestyle.get_parser('', '')
    Linter.add_options(parser)
    options, args = parser.parse_args(argv)
    Linter.parse_options(options)

    data = 'import ast\nimport flake8_import_order\n'
    pycodestyle.stdin_get_value = lambda: data
    checker = Linter(None)
    for lineno, col_offset, msg, instance in checker.run():
        assert msg == 'I201 Missing newline before sections or imports.'

def test_parsing():
    style = 'google'
    import_names = ['flake8_import_order', 'tests']
    package_names = ['local_package']
    argv = [
        "--application-import-names={}".format(','.join(import_names)),
        "--import-order-style={}".format(style),
        "--application-package-names={}".format(','.join(package_names)),
    ]

    parser = pycodestyle.get_parser('', '')
    Linter.add_options(parser)
    options, args = parser.parse_args(argv)
    Linter.parse_options(options)

    assert Linter.options['import_order_style'].name == style
    assert Linter.options['import_order_style'].load() is Google
    assert Linter.options['application_import_names'] == import_names
    assert Linter.options['application_package_names'] == package_names

def test_linter():
    argv = ['--application-import-names=flake8_import_order']
    parser = pycodestyle.get_parser('', '')
    Linter.add_options(parser)
    options, args = parser.parse_args(argv)
    Linter.parse_options(options)

    data = 'import ast\nimport flake8_import_order\n'
    pycodestyle.stdin_get_value = lambda: data
    tree = ast.parse(data)
    checker = Linter(tree, None)
    for lineno, col_offset, msg, instance in checker.run():
        assert msg.startswith(
            'I201 Missing newline between import groups.',
        )

def test_parsing():
    style = 'google'
    import_names = ['flake8_import_order', 'tests']
    package_names = ['local_package']
    argv = [
        "--application-import-names={}".format(','.join(import_names)),
        "--import-order-style={}".format(style),
        "--application-package-names={}".format(','.join(package_names)),
    ]

    parser = pycodestyle.get_parser('', '')
    Linter.add_options(parser)
    options, args = parser.parse_args(argv)
    Linter.parse_options(options)

    assert Linter.options['import_order_style'].name == style
    assert Linter.options['import_order_style'].load() is Google
    assert Linter.options['application_import_names'] == import_names
    assert Linter.options['application_package_names'] == package_names

def run(path, code=None, params=None, **meta):
        """Check code with pycodestyle.

        :return list: List of errors.
        """
        parser = get_parser()
        for option in parser.option_list:
            if option.dest and option.dest in params:
                value = params[option.dest]
                if isinstance(value, str):
                    params[option.dest] = option.convert_value(option, value)

        for key in ["filename", "exclude", "select", "ignore"]:
            if key in params and isinstance(params[key], str):
                params[key] = _parse_multi_options(params[key])

        P8Style = StyleGuide(reporter=_PycodestyleReport, **params)
        buf = StringIO(code)
        return P8Style.input_file(path, lines=buf.readlines())

def get_parser():
    """This returns an instance of optparse.OptionParser with all the
    extensions registered and options set. This wraps ``pep8.get_parser``.
    """
    (extensions, parser_hooks, options_hooks, ignored) = _register_extensions()
    details = ', '.join('%s: %s' % ext for ext in extensions)
    python_version = get_python_version()
    parser = pep8.get_parser('flake8', '%s (%s) %s' % (
        __version__, details, python_version
    ))
    for opt in ('--repeat', '--testsuite', '--doctest'):
        try:
            parser.remove_option(opt)
        except ValueError:
            pass

    if multiprocessing:
        parser.config_options.append('jobs')
        parser.add_option('-j', '--jobs', type='string', default='auto',
                          help="number of jobs to run simultaneously, "
                          "or 'auto'. This is ignored on Windows.")

    parser.add_option('--exit-zero', action='store_true',
                      help="exit with code 0 even if there are errors")

def run(path, code=None, params=None, **meta):
        """Check code with pycodestyle.

        :return list: List of errors.
        """
        parser = get_parser()
        for option in parser.option_list:
            if option.dest and option.dest in params:
                value = params[option.dest]
                if isinstance(value, str):
                    params[option.dest] = option.convert_value(option, value)

        for key in ["filename", "exclude", "select", "ignore"]:
            if key in params and isinstance(params[key], str):
                params[key] = _parse_multi_options(params[key])

        P8Style = StyleGuide(reporter=_PycodestyleReport, **params)
        buf = StringIO(code)
        return P8Style.input_file(path, lines=buf.readlines())