code: function readProduct() {
  
      if (!this.product) {
        throw new Error('Thng does not have a product.');
      }
  
      if (!this.resource) {
        throw new Error('Thng does not have a resource.');
      }
  
      return this.resource.scope.product(this.product).read();
    }
docs: When not using `fetchCascade`, this method allows to easily fetch the Product entity of this Thng. It fowards the call to this thng's scope's product resource.