fList = {7:7, 9:9}

def checkList():
    if not None in fList:
        print(fList)
        fL = random.choice(fList)
        ttt[fL] = computerLetter
        del fList[fL]
        print(fL)
        print(ttt)
        print(fList)

{9: 9, 7: 7}
Traceback (most recent call last):
  File "/home/jason/Desktop/Programming/Python3_5/TestCode.py", line 35,     in <module>
    checkList()
  File "/home/jason/Desktop/Programming/Python3_5/TestCode.py", line 22, in checkList
    fL = random.choice(fList)
  File "/usr/lib/python3.5/random.py", line 265, in choice
    return seq[i]
KeyError: 0