def METHOD_NAME(self, junk: object = None) -> None:
    highlighter_name = self._tab.settings.get("syntax_highlighter", str)
    if highlighter_name == "tree_sitter":
        language_name = self._tab.settings.get("tree_sitter_language_name", str)
        log.info(f"creating a tree_sitter highlighter with language {repr(language_name)}")
        self._highlighter = TreeSitterHighlighter(self._tab.textwidget, language_name)
    elif highlighter_name == "pygments":
        lexer_class = self._tab.settings.get("pygments_lexer", LexerMeta)
        log.info(f"creating a pygments highlighter with lexer class {lexer_class}")
        self._highlighter = PygmentsHighlighter(self._tab.textwidget, lexer_class())
    else:
        log.warning(
            f"bad syntax_highlighter setting {repr(highlighter_name)}, assuming 'pygments'"
        )
        self._tab.settings.set("syntax_highlighter", "pygments")  # runs this again
        return
    self._highlighter.on_scroll()