public function rules(): array 	{ 		return [ 			'provider' => ['required', 'integer', Rule::in(SmsMessage::getAvailableProviders())], 			'from' => ['nullable', 'string', 'max:20'], 			'to' => ['required', 'string', 'max:20', 'phone:AUTO'], 			'body' => ['required', 'string', 'max:1600'], 		]; 	}