Dictionaries with tuples or tuples of tuples

[Jon Reyes]

Thanks Dave and Mitya for enlightening me about dictionaries. I'm still confused about this though:

" so that if two 
key objects are equal, they stay equal, and if they differ, they stay 
different. "

What does this mean? I won't be comparing key objects with one another. Also, when I had two keys with the same value the value of the other key disappeared so I assume in runtime if there are multiple keys of the same value only the last one will appear.