Python 3: Class registry

class_registry.py

"""Implements a class registry based on its name using Python 3 metaclasses

**Source:**

 - https://effectivepython.com/2015/02/02/\
register-class-existence-with-metaclasses/
"""

REGISTRY = {}
"""
    dict: maps the class name into the actual class
"""


class ClassRegistry(type):
    """Saves in the registry each class by its name."""

    def __new__(mcs, name, bases, class_dict):
        cls = type.__new__(mcs, name, bases, class_dict)
        REGISTRY[cls.__name__] = cls
        return cls


class BaseClass:
    """Base class every registered class inherits from."""
    pass


class RegisteredClass(BaseClass, metaclass=ClassRegistry):
    """RegisteredClass accessible from registry upon creation."""
    pass

Class registry with Python 3

Used in bitcoin-framework for Opcode deserialization.