issue in JSON parsing when node type is null

"hypervisor": {
"status": "enabled",
"service":

{ "host": "controller", "disabled_reason": null, ====================Value for this node is null "id": 7 }

,

Since value is null, in JsonToYdtListener/enterJsonNode() disabled_reason is not added to YDT

but in JsonToYdtListener/exitJsonNode() , there is no check that nodeType is null then we should not traverseToParent