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 is_user_addon(mod, user_addon_paths):
        import os

        if not user_addon_paths:
            for path in (bpy.utils.script_path_user(),
                         bpy.utils.script_path_pref()):
                if path is not None:
                    user_addon_paths.append(os.path.join(path, "addons"))

        for path in user_addon_paths:
            if bpy.path.is_subdir(mod.__file__, path):
                return True
        return False