def get_dir_from_zipfile(zip_file, fallback=None):
    """Return the name of the root folder in a zip file.

    :param zip_file: a :class:`zipfile.ZipFile` instance.
    :param fallback: if `None`, the name of the zip file is used. This is
        returned if the zip file contains more than one top-level directory,
        or none at all.
    """
    fallback = fallback or zip_file.filename
    directories = [name for name in zip_file.namelist() if name.endswith("/")
                   and len(PurePath(name).parts) == 1]
    return fallback if len(directories) > 1 else directories[0]
def _make_proxy(self, key, match):
        proxy_type = match.group("type")
        key = match.group("key").strip()
        if proxy_type == "env":
            proxy = EnvProxy(key)
        else:
            proxy = ResolverMethodProxy(self._resolver, proxy_type, key)
        filters = [f for f in [rf.strip() for rf in match.group("filters").split("|")] if f]
        for filter_name in filters:
            if filter_name == "jsondecode":
                proxy = JSONDecodeFilter(proxy)
            elif filter_name == "base64decode":
                proxy = Base64DecodeFilter(proxy)
            elif filter_name.startswith("element:"):
                key = filter_name.split(":", 1)[-1]
                proxy = ElementFilter(key, proxy)
            else:
                raise ValueError("Unknown filter %s", filter_name)
        return proxy