I'm a newbie, but from my understanding you need a "+=" to make sure it captures each string character. Also, "return" shouldn't be embedded in the if statements, because it will stop the for loop from continuing after the just one run, instead of looping for each character. "return" statement should come outside of the for loop, but within the function.

I thought the same too, then I re-read: "...any digit 5 AND above with..."