Read nested Json Mapping with NeoJSON

I have a Json that has this format:

{
  "id": 12,
  "fields": {
    "name": "Hello Pharo"
  }
}

And I would like to import it in a Pharo Object. My Pharo class has two attributes: id, and name. To perform the deserialisation I'm using NeoJSON. I got it for id, but how to map an inner attribute such as name

| reader |
reader := NeoJSONReader on: entity contents readStream.
reader
  for: MyObject
  do: [ :mapping | mapping mapInstVars: #( id ) ].
reader nextAs: MyObject] 

Do you know how one can use the NeoJSON lib to perform such read mapping?

Not my own answer, but I got this asking around:

json := '{
  "id": 12,
  "fields": {
    "name": "Hello Pharo"
  }
}'.

"Use Association as a domain object, key=id, value=fields.name"

reader := NeoJSONReader on: json readStream.
reader for: Association do: [ :mapping |
    mapping mapInstVar: #key to: #id.
    mapping mapProperty: #fields 
        getter: [ :association | { #name -> association value } asDictionary ]
        setter: [ :association :value | association value: (value at: #name) ] ].
reader nextAs: Association. 

    12->'Hello Pharo'.

String streamContents: [ :out |
    (NeoJSONWriter on: out)
        for: Association do: [ :mapping |
            mapping mapInstVar: #key to: #id.
            mapping mapProperty: #fields 
                getter: [ :association | { #name -> association value } asDictionary ]
                setter: [ :association :value | association value: (value at: #name) ] ];
        nextPut: 12 -> 'Hello Pharo' ].

    '{"id":12,"fields":{"name":"Hello Pharo"}}'.