Peter J. Holzer wrote at 2020-10-25 20:48 +0100: >On 2020-10-22 23:35:21 -0700, Julio Di Egidio wrote: > ... >> and the whole lot, indeed why even subclass ABC?
You often have the case that a base class can implement a lot of functionality based on a few methods defined by derived classes. An example is a mapping class (with methods such as keys, values, items, iteration, subscription, ...). All those methods can be implemented generically based on "__len__", "__iter__", "__getitem__" and "__getitem__". In those cases, you can decorate the base methods with `abstractmethod`. Formerly, you had `raise NotImplementedError` in the body of those methods. If a derived class forgot to implement a required method, the exception was raised as soon as the method was called. With `abstractmethod` you see the problem earlier. -- https://mail.python.org/mailman/listinfo/python-list
