util.py 文件源码

def _check_importer_for_path(name, path_item):
    try:
        importer = sys.path_importer_cache[path_item]
    except KeyError:
        for path_hook in sys.path_hooks:
            try:
                importer = path_hook(path_item)
                break
            except ImportError:
                pass
        else:
            importer = None
        sys.path_importer_cache.setdefault(path_item, importer)


    if importer is None:
        try:
            return imp.find_module(name, [path_item])
        except ImportError:
            return None
    return importer.find_module(name)