I see there is a possibility that the function created here can falsely report the case.
if should be "ContainsAllDigits"
Problem here is the current function is looking any number within the string, so if there happens to be
Letters before or after for example, the function will falsely report a numerical string.
I know in reality if things are going well the string should be all digits, but in the case of getting software to
work I think it should fail if the string isn't all numerical digits, don't you think ?