{"indexes":[{"v":{"$numberInt":"2"},"key":{"_id":{"$numberInt":"1"}},"name":"_id_"},{"v":{"$numberInt":"2"},"key":{"registration_number":{"$numberInt":"1"}},"name":"registration_number_1","background":true}],"uuid":"a4d8e84171214a29baf16897819112d0","collectionName":"event_participant","type":"collection"}