|string> */ public function rules(): array { return [ 'product_id' => 'required', 'next_due_date' => 'required', 'next_payment' => 'required', 'name' => 'required', 'module_server_id' => 'required', 'user' => 'required', 'password' => 'required', 'status' => 'required' ]; } }