registry.py

fromtypingimportDict


classRegistryHolder(type):

REGISTRY: Dict[str, "RegistryHolder"] = {}

def__new__(cls, name, bases, attrs):
new_cls=type.__new__(cls, name, bases, attrs)
"""
 Here the name of the class is used as key but it could be any class
 parameter.
 """
cls.REGISTRY[new_cls.__name__] =new_cls
returnnew_cls

@classmethod
defget_registry(cls):
returndict(cls.REGISTRY)


classBaseRegisteredClass(metaclass=RegistryHolder):
"""
 Any class that will inherits from BaseRegisteredClass will be included
 inside the dict RegistryHolder.REGISTRY, the key being the name of the
 class and the associated value, the class itself.
 """


defmain():
"""
 Before subclassing
 >>> sorted(RegistryHolder.REGISTRY)
 ['BaseRegisteredClass']

 >>> class ClassRegistree(BaseRegisteredClass):
 ... def __init__(self, *args, **kwargs):
 ... pass

 After subclassing
 >>> sorted(RegistryHolder.REGISTRY)
 ['BaseRegisteredClass', 'ClassRegistree']
 """


if__name__=="__main__":
importdoctest

doctest.testmod(optionflags=doctest.ELLIPSIS)