public function filter(array $jobs, $time = null)
    {
        $dues = $cache = [];
        $time = $this->normalizeTime($time);

        foreach ($jobs as $name => $expr) {
            $expr = $this->normalizeExpr($expr);

            if (!isset($cache[$expr])) {
                $cache[$expr] = $this->isCronDue($expr, $time);
            }

            if ($cache[$expr]) {
                $dues[] = $name;
            }
        }

        return $dues;
    }