def template_dir(self):
        r"""
        Set the path to the directory containing the Excel template files (with '.crtx' extension).
        This method is mainly useful if your template files are located in several directories,
        otherwise pass the template directory directly the ExcelReport constructor.

        Parameters
        ----------
        template_dir : str or Path
            Path to the directory containing the Excel template files.

        See Also
        --------
        set_graph_template

        Examples
        --------
        >>> report = ExcelReport(EXAMPLE_EXCEL_TEMPLATES_DIR)
        >>> # ... add some graphs using template files from 'C:\excel_templates_dir'
        >>> report.template_dir = r'C:\other_templates_dir' # doctest: +SKIP
        >>> # ... add some graphs using template files from 'C:\other_templates_dir'
        """
        return self._template_dir