为什么我的for循环只迭代一次?

I am writing a Hangman program. I'm having trouble with my function which handles a character guess from the user. The issue I have is that my for loop only seems to be iterating once and I cannot work out why. This is an assignment so I'm not asking for specific code in reply but a point in the right direction would be good. Thanks, here's the function: I am writing a Hangman program. I'm having trou