How to add a role to an existing user account using Component Interface?

Hi, I am able to use the following code section that I have in an application engine to update the existing role (Test_Role1) for a PeopleSoft User Account to a different role. However, I want to add an additional role, and I was wondering how that can be done. I have only copied parts of the code to show that the getting history rows and updating them is turned on and also included the section that's used for adding/modifying a role.

I have tested a couple of methods and wasn't able to add an additional role. If you have done this, could you please share with me how you were able to accomplish that?