__init__.py 文件源码

def __init__(cls, what, bases=None, dict=None):
    super(AdapterMeta, cls).__init__(what, bases, dict)

    if not is_abstract(cls):
      for protocol in getattr(cls, 'supported_protocols', ()):
        # Note that we will not overwrite existing registered adapters.
        adapter_registry.setdefault(protocol, cls)