Update json data with context in Python using jsonpath-ng

following Update json nodes in Python using jsonpath, would like to know how one might update the JSON data given a certain context. So, say we pick the exact same JSON example:

{
    "SchemeId": 10,
    "nominations": [
        {
            "nominationId": 1
        }
    ]
}

But this time, would like to double the value of the original value, hence some lambda function is needed which takes into account the current node value.

No need for lambdas; for example, to double SchemeId, something like this should work:

data = json.loads("""the json string above""")
jsonpath_expr = parse('$.SchemeId')
jsonpath_expr.find(data)
val = jsonpath_expr.find(data)[0].value
jsonpath_expr.update(data, val*2)
print(json.dumps(data, indent=2))

Output:

{
  "SchemeId": 20,
  "nominations": [
    {
      "nominationId": 1
    }
  ]
}