Merge SortedList and SortedKeyList Into a Single Class #248
Description
From what I can tell, SortedList and SortedKeyList are functionally interchangeable aside from the slight memory overhead of the SortedKeyList._keys list in SortedKeyList. A simpler implementation would be to use SortedKeyList for everything and default the key to the identity function, which is actually already the case for SortedKeyList. This would allow removal of the custom SortedList.__new__ function and, more importantly, properly type hint the classes and methods without getting invalid signatures.
Is there are concrete reason these classes exist separately other than the small overhead associated with SortedKeyList._keys?