average daily unique user measure for month/Week

I am trying to build average daily unique user measure for month dimension in workspace .

I could achieve the daily average Number for additive measure like pageview, but I couldn’t find any solution available in experience league for user measure . How could we build ‘average daily unique user’ calculated measure for month dimension /date component ? I below screen shot – I am looking for ‘Mean Unique Visitor ’ day value in month granularity