Editing Dictionaries

[ichabod801]

To add to what jcrater said, you can totally simplify your loop:

for Pair in (A, E, U):
    Pair['Bi'] = Pair + 'b'
    ...

Of course, you will get another error on Pair['Bi'] = Pair + 'b', because you are trying to add a dictionary to a string, which won't work. But it's not clear to me what you're expecting to happen there, so I'm not sure how to fix it.