* This is a very long code just to write "you must implement this method". Having a standard way to say that is better.
* You can instantiate the base class, which doesn't make sense.
* You must use testing to check whether a concrete class which you derived from the base class really implemented all the abstract methods. Testing is a good thing, but it seems to me that when the code specifies exactly what should happen, and it doesn't make sense for it not to happen, there's no point in having a separate test for it.
About the possibility of implementing only a subset of the interface: You are perfectly welcomed to implement any part of the interface as you like. Function which use only what you've implemented should work fine with your classes. But you can't claim your classes to be instances of the base class - as I see it, subclasses, even in Python, guarantee to behave like their base classes.
Have a good day, Noam -- http://mail.python.org/mailman/listinfo/python-list
