def on_env(
        self, env: jinja2.Environment, /, *, config: MkDocsConfig, files: Files
    ) -> jinja2.Environment | None:
        """
        The `env` event is called after the Jinja template environment is created
        and can be used to alter the
        [Jinja environment](https://jinja.palletsprojects.com/en/latest/api/#jinja2.Environment).

        Args:
            env: global Jinja environment
            config: global configuration object
            files: global files collection

        Returns:
            global Jinja Environment
        """
        return env

        The `env` event is called after the Jinja template environment is created
        and can be used to alter the
        [Jinja environment](https://jinja.palletsprojects.com/en/latest/api/#jinja2.Environment).

        Args:
            env: global Jinja environment
            config: global configuration object
            files: global files collection

        Returns:
            global Jinja Environment
        
mkdocs/plugins.py