How to pass null as input parameter in SAP HANA XSJob

How can we pass null as input parameter in XSJob Scheduler file. If passed as below file is not getting activated.

{ "description": "Daily Job ", "action": "PROCEDURE", "schedules": [{ "description": "Daily: Single Run @**", "xscron": "* * * * 5 50 10", "parameter": { "IP_1": null, "IP_2": null, "IP_3": null } }] } .

Tried multiple approaches,nothing works

1."parameter": { "IP_1": "null", "IP_2": "null", "IP_3": "null" }

2."parameter": { "IP_1": , "IP_2": , "IP_3": }

3."parameter": { "IP_1": null, "IP_2": null, "IP_3": null }