public function isClassTaggedWith($className, $tag)
    {
        if ($this->initialized === false) {
            return false;
        }
        if (!isset($this->reflectedClassNames[$className])) {
            $this->reflectClass($className);
        }
        if (!isset($this->classTagsValues[$className])) {
            return false;
        }
        return isset($this->classTagsValues[$className][$tag]);
    }