Arcade Expression

[BSBlagojevic]

Please, is any known how to get unique values from tables with many repeating, which I need in my report? I try with simple table query as below, but without success! Please, help me! As assistance attached both tables. In first table I need Unique's from field 'TipAlteracije' from second field 'Naziv'

Thank you very much! 

Distinct($featureSet, ["FieldName"])

[Robert_LeClair]

If you don't need to run Python, then the Frequency (Analysis Tools) | ArcGIS Pro documentation will do the job easily enough.