abc.py 文件源码

def __new__(mcls, name, bases, namespace, **kwargs):
        cls = super().__new__(mcls, name, bases, namespace, **kwargs)
        # Compute set of abstract method names
        abstracts = {name
                     for name, value in namespace.items()
                     if getattr(value, "__isabstractmethod__", False)}
        for base in bases:
            for name in getattr(base, "__abstractmethods__", set()):
                value = getattr(cls, name, None)
                if getattr(value, "__isabstractmethod__", False):
                    abstracts.add(name)
        cls.__abstractmethods__ = frozenset(abstracts)
        # Set up inheritance registry
        cls._abc_registry = WeakSet()
        cls._abc_cache = WeakSet()
        cls._abc_negative_cache = WeakSet()
        cls._abc_negative_cache_version = ABCMeta._abc_invalidation_counter
        return cls