How to use the httpie.plugins.plugin_manager function in httpie

def test_auth_plugin_parse_auth_false(httpbin):

    class Plugin(AuthPlugin):
        auth_type = 'test-parse-false'
        auth_parse = False

        def get_auth(self, username=None, password=None):
            assert username is None
            assert password is None
            assert self.raw_auth == BASIC_AUTH_HEADER_VALUE
            return basic_auth(self.raw_auth)

    plugin_manager.register(Plugin)
    try:
        r = http(
            httpbin + BASIC_AUTH_URL,
            '--auth-type',
            Plugin.auth_type,
            '--auth',
            BASIC_AUTH_HEADER_VALUE,
        )
        assert HTTP_OK in r
        assert r.json == AUTH_OK
    finally:
        plugin_manager.unregister(Plugin)

def test_auth_plugin_prompt_password_false(httpbin):

    class Plugin(AuthPlugin):
        auth_type = 'test-prompt-false'
        prompt_password = False

        def get_auth(self, username=None, password=None):
            assert self.raw_auth == USERNAME
            assert username == USERNAME
            assert password is None
            return basic_auth()

    plugin_manager.register(Plugin)

    try:
        r = http(
            httpbin + BASIC_AUTH_URL,
            '--auth-type',
            Plugin.auth_type,
            '--auth',
            USERNAME,
        )
        assert HTTP_OK in r
        assert r.json == AUTH_OK
    finally:
        plugin_manager.unregister(Plugin)

def auth(self) -> Optional[AuthBase]:
        auth = self.get('auth', None)
        if not auth or not auth['type']:
            return

        plugin = plugin_manager.get_auth_plugin(auth['type'])()

        credentials = {'username': None, 'password': None}
        try:
            # New style
            plugin.raw_auth = auth['raw_auth']
        except KeyError:
            # Old style
            credentials = {
                'username': auth['username'],
                'password': auth['password'],
            }
        else:
            if plugin.auth_parse:
                from httpie.cli.argtypes import parse_auth
                parsed = parse_auth(plugin.raw_auth)
                credentials = {

def main(argv=sys.argv):
    args = parse(argv)
    """Serve up some ponies."""
    hostname = args.listen
    port = args.port
    print(
        "Making all your dreams for a pony come true on http://{0}:{1}.\n"
        "Press Ctrl+C to quit.\n".format(hostname, port)
    )

    # Hush, werkzeug.
    logging.getLogger("werkzeug").setLevel(logging.CRITICAL)

    plugin_manager.load_installed_plugins()
    app = make_app()
    run_simple(hostname, port, app)

def __iter__(self):
        return iter(sorted(plugin_manager.get_auth_plugin_mapping().keys()))

args: List[Union[str, bytes]] = sys.argv,
    env=Environment(),
) -> ExitStatus:
    """
    The main function.

    Pre-process args, handle some special types of invocations,
    and run the main program with error handling.

    Return exit status code.

    """
    program_name, *args = args
    env.program_name = os.path.basename(program_name)
    args = decode_raw_args(args, env.stdin_encoding)
    plugin_manager.load_installed_plugins()

    from httpie.cli.definition import parser

    if env.config.default_options:
        args = env.config.default_options + args

    include_debug_info = '--debug' in args
    include_traceback = include_debug_info or '--traceback' in args

    if include_debug_info:
        print_debug_info(env)
        if args == ['--debug']:
            return ExitStatus.SUCCESS

    exit_status = ExitStatus.SUCCESS

def __contains__(self, item):
        return item in plugin_manager.get_auth_plugin_mapping()