code: function BoundJSONGraphModelError() {
      var instance = new Error("It is not legal to use the JSON Graph " +
      "format from a bound Model. JSON Graph format" +
      " can only be used from a root model.");
  
      instance.name = "BoundJSONGraphModelError";
  
      if (Object.setPrototypeOf) {
          Object.setPrototypeOf(instance, Object.getPrototypeOf(this));
      }
  
      if (Error.captureStackTrace) {
          Error.captureStackTrace(instance, BoundJSONGraphModelError);
      }
  
      return instance;
  }
docs: When a bound model attempts to retrieve JSONGraph it should throw an
  error.
  
  @private