How to use the keystonemiddleware.auth_token._cache.TokenCache function in keystonemiddleware

use_advanced_pool=self._conf.get('memcache_use_advanced_pool'),
            dead_retry=self._conf.get('memcache_pool_dead_retry'),
            maxsize=self._conf.get('memcache_pool_maxsize'),
            unused_timeout=self._conf.get('memcache_pool_unused_timeout'),
            conn_get_timeout=self._conf.get('memcache_pool_conn_get_timeout'),
            socket_timeout=self._conf.get('memcache_pool_socket_timeout'),
        )

        if security_strategy.lower() != 'none':
            secret_key = self._conf.get('memcache_secret_key')
            return _cache.SecureTokenCache(self.log,
                                           security_strategy,
                                           secret_key,
                                           **cache_kwargs)
        else:
            return _cache.TokenCache(self.log, **cache_kwargs)

use_advanced_pool=self._conf_get('memcache_use_advanced_pool'),
            dead_retry=self._conf_get('memcache_pool_dead_retry'),
            maxsize=self._conf_get('memcache_pool_maxsize'),
            unused_timeout=self._conf_get('memcache_pool_unused_timeout'),
            conn_get_timeout=self._conf_get('memcache_pool_conn_get_timeout'),
            socket_timeout=self._conf_get('memcache_pool_socket_timeout'),
        )

        if security_strategy:
            secret_key = self._conf_get('memcache_secret_key')
            return _cache.SecureTokenCache(self.log,
                                           security_strategy,
                                           secret_key,
                                           **cache_kwargs)
        else:
            return _cache.TokenCache(self.log, **cache_kwargs)

return jsonutils.loads(data)

    def set(self, token_id, data):
        """Store value into memcache."""
        data = jsonutils.dumps(data)
        if isinstance(data, six.text_type):
            data = data.encode('utf-8')

        cache_key, context = self._get_cache_key(token_id)
        data_to_store = self._serialize(data, context)

        with self._cache_pool.reserve() as cache:
            cache.set(cache_key, data_to_store, time=self._cache_time)


class SecureTokenCache(TokenCache):
    """A token cache that stores tokens encrypted.

    A more secure version of TokenCache that will encrypt tokens before
    caching them.
    """

    def __init__(self, log, security_strategy, secret_key, **kwargs):
        super(SecureTokenCache, self).__init__(log, **kwargs)

        if not secret_key:
            msg = _('memcache_secret_key must be defined when a '
                    'memcache_security_strategy is defined')
            raise exc.ConfigurationError(msg)

        if isinstance(security_strategy, six.string_types):
            security_strategy = security_strategy.encode('utf-8')