can't set value in jolt with modify-overwrite-beta

[#1]

I want to create new node(seed) and set value to that
but my code not working. I this my path in modify-overwrite-beta is wrong.

"ai":{
      "model_structure":{
            "backend":"tensorflow",
	    "seed":100,
             "model_type":"Deep"
   }

{
    "operation": "modify-overwrite-beta",
    "spec": {
      "jobInput": {
        "ai": {
          "common": {
            "seed": "=@(ai.model_structure.seed)"
          }
        }
      }
    }
  }

[#2]

it is the answer
```

{
"operation": "modify-overwrite-beta",
"spec": {
"jobInput": {
"ai": {
"common": {
"seed": "@(4,ai.model_structure.seed)"
}
}
}
}
}

@(4,ai.model_structure.seed) means backward 4step on json tree and use seed with path(ai.model_structure.seed).