[Flow] initialize MemcacheBackend

[Peter R]

Hello,

I try to get MemcachedBackend work, but I have a problem with setCache.
What comes into the parenthesize?

$options = array(
    'servers' => array('localhost:11211'),
);
$memcache = new MemcachedBackend($this->environment->getContext(), $options);
$memcache->setCache(TYPO3\Flow\Cache\Frontend\FrontendInterface); ?????

$memcache->set('key', $value);

echo $memcache->get('key');

Peter