public function rules(): array 	{ 		return [ 			'order_number' => ['required', 'string', 'size:36', 'exists:orders,order_number'], 			'language' => ['required', 'string', 'size:2'], 			'approval_code' => ['required', 'string'], 			'signature' => ['required', 'string', 'max:64'], 		]; 	}