Generic version of ABCMetaImplementAnyOneOf.

Inherits From: GenericMeta, ABCMetaImplementAnyOneOf

Classes which inherit from Generic[T] must use this type instead of ABCMetaImplementAnyOneOf due to

This issue is specific to python3.6; this class can be removed when Cirq python3.6 support is turned down.



Register a virtual subclass of an ABC.

Returns the subclass, to allow usage as a class decorator.