public void setArn(String arn) {
        this.arn = arn;
    }
<p>
The Amazon Resource Name (ARN) of the principal that performed the action. The last section of the ARN contains
the name of the user who performed the action.
</p>

@param arn
       The Amazon Resource Name (ARN) of the principal that performed the action. The last section of the ARN
       contains the name of the user who performed the action.
aws-java-sdk-macie2/src/main/java/com/amazonaws/services/macie2/model/IamUser.java