def export_report(ss, report_id, export_format, export_path, sheet_name):
    """
    Exports a report, given export filetype and location. Allows export format 'csv' or 'xlsx'.
    :param ss:              initialized smartsheet client instance
    :param report_id:       int, required; report id
    :param export_format:   str, required; 'csv' or 'xlsx'
    :param export_path:     str, required; filepath to export sheet to
    :param sheet_name:      str, required; name of sheet exported
    :return:                str, indicating failure or success, with path, filename, extension
    """

    if export_format == 'csv':
        ss.Sheets.get_sheet_as_csv(report_id, export_path)
    elif export_format == 'xlsx':
        ss.Sheets.get_sheet_as_excel(report_id, export_path)

    if export_format == 'csv' or export_format == 'xlsx':
        return 'Report exported to {}{}.{}'.format(export_path, sheet_name, export_format)
    else:
        return 'export_format \'{}\' is not valid. Must be \'csv\' or \'xlsx\''.format(export_format)