What is the correct way to use combine from within a nested `ObservableObject`?

Using Swift
1 
import Combine

class ModelData: ObservableObject {
    @Published var nestedObservableObject = NestedObservableObject()

  init(database: AppDatabase) {

      anyCancellable = nestedObservableObject.objectWillChange.sink { [weak self] (_) in
            self?.objectWillChange.send()
        }

    // this does not work, cannot print anything when stringIWant changes
      var myCancellable = nestedObservableObject.$aStruct.sink { aStruct in
           print("myCancellable observed changes: \(aStruct.stringIWant)")
       }
  }

class NestedObservableObject: ObservableObject {
    @Published var aStruct: aStruct?
}

struct PTTelemetryEvent {
    var stringIWant: String = ""
}

Hey everyone, what would be the proper way to use combine when dealing with the nested ObservableObject?