public function invalidateCache($source, $context)
    {
        $key = $this->getSpecificSourceCacheKey(
            $source,
            $context
        );

        $this
            ->cache
            ->delete($this->getSpecificSourceCacheKey(
                $source,
                $context
            ));

        unset($this->commentTree[$key]);

        return $this;
    }