def on_page_markdown(
        self, markdown: str, /, *, page: Page, config: MkDocsConfig, files: Files
    ) -> str | None:
        """
        The `page_markdown` event is called after the page's markdown is loaded
        from file and can be used to alter the Markdown source text. The meta-
        data has been stripped off and is available as `page.meta` at this point.

        Args:
            markdown: Markdown source text of page as string
            page: `mkdocs.structure.pages.Page` instance
            config: global configuration object
            files: global files collection

        Returns:
            Markdown source text of page as string
        """
        return markdown

        The `page_markdown` event is called after the page's markdown is loaded
        from file and can be used to alter the Markdown source text. The meta-
        data has been stripped off and is available as `page.meta` at this point.

        Args:
            markdown: Markdown source text of page as string
            page: `mkdocs.structure.pages.Page` instance
            config: global configuration object
            files: global files collection

        Returns:
            Markdown source text of page as string
        
mkdocs/plugins.py