def get_trader_index(data) -> list:
    """Get trader index"""

    return [i['@TraderID'] for i in (data.get('NEMSPDCaseFile')
                                     .get('NemSpdInputs')
                                     .get('PeriodCollection')
                                     .get('Period')
                                     .get('TraderPeriodCollection')
                                     .get('TraderPeriod'))]