method numerous times.
        format : dict, list of dict
            Keyword args to pass to the method call of ``Styler.format``. If a list will
            call the method numerous times.
        format_index : dict, list of dict
            Keyword args to pass to the method call of ``Styler.format_index``. If a
            list will call the method numerous times.
        render_kwargs : dict
            Keyword args to pass to the method call of ``Styler.to_latex``.

        Returns
        -------
        str or None
            If buf is None, returns the result as a string. Otherwise returns None.
        r