capitalization of library class names

Question

Why do collection.defaultdict and collection.OrderedDict have different capitalizations?

Is there some subtle difference that I should be a

Answer 1

The capitalization of the class names is irrelevant, it doesn't signify anything. Except that Python has sometimes grown organically and the standard library doesn't have the same homogenous feel as other large libraries such as the Win32 API or the Java standard library.