Sort RSS feed alphabetically (code)

I would like to sort my RSS feed in alphabetical order, but I cannot find the right piece of code, and where to put it in.

I have been googling for the last few hours, but without any success. I understand that I can just add a piece of code into my function file and this is the easiest solution.

Could somebody provide me the right code to write so I can sort my RSS feed in alphabetical order? (From A-Z)