langhelpers.py 文件源码

def load(self, name):
        if name in self.impls:
            return self.impls[name]()

        if self.auto_fn:
            loader = self.auto_fn(name)
            if loader:
                self.impls[name] = loader
                return loader()

        try:
            import pkg_resources
        except ImportError:
            pass
        else:
            for impl in pkg_resources.iter_entry_points(
                    self.group, name):
                self.impls[name] = impl.load
                return impl.load()

        raise exc.NoSuchModuleError(
            "Can't load plugin: %s:%s" %
            (self.group, name))