This package implements a metaclass and convenience instance of it that works like abc.ABC, but allows you to customize what happens when the class object gets called by implementing a _class_call() classmethod.
Inherit from the convenience class CallableABC to get this behavior,
or use the metaclass CallableABCMeta directly.
The metaclass uses the CallableABCMetaDict dictionary subclass to keep track of the _class_call() method.