t) {
                const fragment = document.createDocumentFragment();
                
                newItems.forEach((item, index) => {
                    const key = String(keyFn(item, index));
                    const element = createItemElement(item, index, renderItem, key, context);
                    if (element) fragment.appendChild(element);
                });
                
                parentElement.appendChild(fragment);
                return null;
            }

            functi