Need help to default the value of Grade in Worker Assignment

Summary:

We have a requirement to default on the value of Grade in Worker Assignment. The Grade Name value will be coming from the UDT with a combination of several fields including Flexfields from Assignment as parameter. I was able to get the Grade Name using the function 'Get String Value from Value Set.'  

However, I can't use the Grade Name directly to default the Grade field. Is there a way to get the Grade ID using the Grade Name as parameter?

Is there any other alternative way to do it? Thanks for your help.

Use Case: 104

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