How to use the @aws-cdk/aws-cloudwatch-actions.SnsAction function in @aws-cdk/aws-cloudwatch-actions

}),
      threshold: 0,
      evaluationPeriods: 1,
      datapointsToAlarm: 1,
      treatMissingData: cloudwatch.TreatMissingData.NOT_BREACHING,
      alarmDescription: "Detect errors",
      alarmName: "cloudtrail_partitioner_errors"
    });

    // Create SNS for alarms to be sent to
    const sns_topic = new sns.Topic(this, 'cloudtrail_partitioner_alarm', {
      displayName: 'cloudtrail_partitioner_alarm'
    });

    // Connect the alarm to the SNS
    error_alarm.addAlarmAction(new cloudwatch_actions.SnsAction(sns_topic));

    // Create Lambda to forward alarms
    const alarm_forwarder = new lambda.Function(this, "alarm_forwarder", {
      runtime: lambda.Runtime.PYTHON_3_7,
      code: lambda.Code.asset("resources/alarm_forwarder"),
      handler: "main.handler",
      description: "Forwards alarms from the local SNS to another",
      logRetention: logs.RetentionDays.TWO_WEEKS,
      timeout: cdk.Duration.seconds(30),
      memorySize: 128,
      environment: {
        "ALARM_SNS": config['alarm_sns_arn']
      },
    });

    // Add priv to publish the events so the alarms can be forwarded

}),
      threshold: 0,
      evaluationPeriods: 1,
      datapointsToAlarm: 1,
      treatMissingData: cloudwatch.TreatMissingData.NOT_BREACHING,
      alarmDescription: "Detect errors",
      alarmName: "cloudmapper_errors"
    });

    // Create SNS for alarms to be sent to
    const sns_topic = new sns.Topic(this, 'cloudmapper_alarm', {
      displayName: 'cloudmapper_alarm'
    });

    // Connect the alarm to the SNS
    error_alarm.addAlarmAction(new cloudwatch_actions.SnsAction(sns_topic));

    // Create Lambda to forward alarms
    const alarm_forwarder = new lambda.Function(this, "alarm_forwarder", {
      runtime: lambda.Runtime.PYTHON_3_7,
      code: lambda.Code.asset("resources/alarm_forwarder"),
      handler: "main.handler",
      description: "Forwards alarms from the local SNS to another",
      logRetention: logs.RetentionDays.TWO_WEEKS,
      timeout: cdk.Duration.seconds(30),
      memorySize: 128,
      environment: {
        "ALARM_SNS": config['alarm_sns_arn']
      },
    });

    // Add priv to publish the events so the alarms can be forwarded