public function contains(array $list)
    {
        phpCAS::traceBegin();
        $count = 0;
        foreach ($this->_chains as $chain) {
            phpCAS::trace("Checking chain ". $count++);
            if ($chain->matches($list)) {
                phpCAS::traceEnd(true);
                return true;
            }
        }
        phpCAS::trace("No proxy chain matches.");
        phpCAS::traceEnd(false);
        return false;
    }