This function is supposed to add a name and number to the dictionary 'phoneBook' when I run the loop, but for some reason I can't get it to work. Any ideas on why not? Thanks a lot!

```
 phoneBook = dict()
    def addNumber(name, number):
        for i in phoneBook:
            if i == name:
                print 'error'
            else:
                phoneBook[name] = number

```