def METHOD_NAME(username, registry):
    """Given a username, delete the account key from the cache."""
    hmac_secret = registry.settings["userid_hmac_secret"]
    cache_key = utils.hmac_digest(hmac_secret, ACCOUNT_CACHE_KEY.format(username))
    cache = registry.cache
    cache_result = cache.delete(cache_key)
    return cache_result