What are you trying to modify inside of %DeepSee.Dashboard.Utils?

I tried this and it worked:

Parameter TestParam = "Test";

Property TestCalc As %String [ SqlComputeCode = { Set {*} = ..#TestParam}, SqlComputed ];

[SQL]SAMPLES>>select * from DC.SQLCompute
1.      select * from DC.SQLCompute
 
ID      TestCalc
1       Test

Here is a quick video about databases and namespaces that may help you get started with your plan for what is needed:

https://learning.intersystems.com/course/view.php?id=1130