Inheritance: extends Mage2\Framework\System\Models\BaseModel
 public function saveRelatedProducts($product, ProductRequest $request)
 {
     if (count($request->get('related_products')) > 0) {
         $relatedProducts = [];
         RelatedProduct::where('product_id', '=', $product->id)->delete();
         foreach ($request->get('related_products') as $relatedId) {
             $relatedProducts = ['product_id' => $product->id, 'related_product_id' => $relatedId];
             RelatedProduct::create($relatedProducts);
         }
     }
 }