How to use the radian.lexer.CustomSLexer function in radian

multiline=settings.indent_lines,
        complete_while_typing=settings.complete_while_typing,
        lexer=None,
        completer=SmartPathCompleter(),
        prompt_key_bindings=create_shell_key_bindings()
    )
    session.register_mode(
        "browse",
        activator=browse_activator,
        # on_pre_accept=browse_on_pre_accept,  # disable
        insert_new_line=True,
        history_share_with="r",
        get_message=lambda: settings.browse_prompt.format(session.browse_level),
        multiline=settings.indent_lines,
        complete_while_typing=True,
        lexer=PygmentsLexer(SLexer),
        completer=RCompleter(timeout=settings.completion_timeout),
        input_processors=input_processors,
        prompt_key_bindings=create_r_key_bindings(prase_text_complete),
        switchable_from=False,
        switchable_to=False
    )
    session.register_mode(
        "unknown",
        insert_new_line=False,
        get_message=lambda: session.prompt_text,
        complete_while_typing=False,
        lexer=None,
        completer=None,
        prompt_key_bindings=None,
        switchable_from=False,
        switchable_to=False,

text = session.default_buffer.text
        shell.run_command(text)

    input_processors = []
    if settings.highlight_matching_bracket:
        input_processors.append(HighlightMatchingBracketProcessor())

    session.register_mode(
        "r",
        activator=lambda session: session.prompt_text == settings.prompt,
        insert_new_line=True,
        history_share_with="browse",
        get_message=lambda: settings.prompt,
        multiline=settings.indent_lines,
        complete_while_typing=settings.complete_while_typing,
        lexer=PygmentsLexer(SLexer),
        completer=RCompleter(),
        key_bindings=create_key_bindings(),
        input_processors=input_processors,
        prompt_key_bindings=create_r_key_bindings(prase_text_complete)
    )
    session.register_mode(
        "shell",
        on_post_accept=shell_process_text,
        insert_new_line=True,
        get_message=lambda: settings.shell_prompt,
        multiline=settings.indent_lines,
        complete_while_typing=settings.complete_while_typing,
        lexer=None,
        completer=SmartPathCompleter(),
        prompt_key_bindings=create_shell_key_bindings()
    )

text = session.default_buffer.text
        shell.run_command(text)

    input_processors = []
    if settings.highlight_matching_bracket:
        input_processors.append(HighlightMatchingBracketProcessor())

    session.register_mode(
        "r",
        activator=lambda session: session.prompt_text == settings.prompt,
        insert_new_line=True,
        history_share_with="browse",
        get_message=lambda: settings.prompt,
        multiline=settings.indent_lines,
        complete_while_typing=settings.complete_while_typing,
        lexer=PygmentsLexer(SLexer),
        completer=RCompleter(timeout=settings.completion_timeout),
        key_bindings=create_key_bindings(),
        input_processors=input_processors,
        prompt_key_bindings=create_r_key_bindings(prase_text_complete)
    )
    session.register_mode(
        "shell",
        on_post_accept=shell_process_text,
        insert_new_line=True,
        get_message=lambda: settings.shell_prompt,
        multiline=settings.indent_lines,
        complete_while_typing=settings.complete_while_typing,
        lexer=None,
        completer=SmartPathCompleter(),
        prompt_key_bindings=create_shell_key_bindings()
    )

multiline=settings.indent_lines,
        complete_while_typing=settings.complete_while_typing,
        lexer=None,
        completer=SmartPathCompleter(),
        prompt_key_bindings=create_shell_key_bindings()
    )
    session.register_mode(
        "browse",
        activator=browse_activator,
        # on_pre_accept=browse_on_pre_accept,  # disable
        insert_new_line=True,
        history_share_with="r",
        get_message=lambda: settings.browse_prompt.format(session.browse_level),
        multiline=settings.indent_lines,
        complete_while_typing=True,
        lexer=PygmentsLexer(SLexer),
        completer=RCompleter(),
        input_processors=input_processors,
        prompt_key_bindings=create_r_key_bindings(prase_text_complete),
        switchable_from=False,
        switchable_to=False
    )
    session.register_mode(
        "unknown",
        insert_new_line=False,
        get_message=lambda: session.prompt_text,
        complete_while_typing=False,
        lexer=None,
        completer=None,
        prompt_key_bindings=None,
        switchable_from=False,
        switchable_to=False,