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 each(f):
        if f.body:
            f.hashes = []
            for hash_type, h in HashFile.extract_hashes(f.body.contents):
                hash_object = Hash.get_or_create(value=h.hexdigest())
                hash_object.add_source("analytics")
                hash_object.save()
                f.active_link_to(
                    hash_object,
                    "{} hash".format(hash_type.upper()),
                    "HashFile",
                    clean_old=False,
                )
                f.hashes.append({"hash": hash_type, "value": h.hexdigest()})
            f.save()