How to *return* Binary of decimal in recursion code Python

Learning Recursion. I was able to write Python code to print binary number using recursion but couldn’t figure out how to return this binary number. I am only getting the first mod value when I return, probably because, as I understand, the stack folds back to the beginning by the time it can return. (Hope this is not wrong). I would greatly appreciate if you could not only provide your answer to get the function to return the result but also explain how it works.