python language

Write a function scramble that takes a string and returns that string with all the even characters and odd characters swapped. For example, if the function is called with the string containing the phrase How are you? The function will return oH wra eoy?u. You are not allowed to use any built-in Python string methods or other data types (like a list) - you need to come up with your own algorithm, but you are allowed to use built-in functions such as range and len Show a couple of sample calls to this function