anchor.diff:  abstract class VaneModel {
     static Validator _v = new Validator();
   
  -  static dynamic decode(json, model, {bool validate: true}) {
  +  static dynamic decode(json, model, {bool validate: true, bool observe: false}) {
       // Return correct type if we got empty json data (responses from APIs or
       // databases can be empty if no data was found for example)
       if(json is String) {
  
positive.code:         document = json;
        }
  
        return model.fromDocument(document);
      }
  
      /*
  
negative.code:             var element;
  
              if(vmm.members[key].isBasic == true) {
  //              print("--> Before assigning base type, key = ${key}");
  
                // Use value directly from document if we expect a basic type
                element = document[key];
              } else {
  