pure_interface.py 文件源码

def _type_is_pure_interface(cls):
    """ Return True if cls is a pure interface or an empty ABC class"""
    if cls is object:
        return False
    if hasattr(cls, '_pi'):
        return cls._pi.type_is_pure_interface
    if issubclass(type(cls), abc.ABCMeta):
        for attr, value in six.iteritems(cls.__dict__):
            if _builtin_attrs(attr):
                continue
            if callable(value):
                if not _is_empty_function(value):
                    return False
            elif isinstance(value, property):
                for func in (value.fget, value.fset, value.fdel):
                    if func is not None and not _is_empty_function(func):
                        return False
        return True

    return False