items = $items; } public function __toString(): string { $items = $this->items; return 'object{' . implode(', ', $items) . '}'; } /** * @param array $properties */ public static function __set_state(array $properties): self { $instance = new self($properties['items']); if (isset($properties['attributes'])) { foreach ($properties['attributes'] as $key => $value) { $instance->setAttribute($key, $value); } } return $instance; } }