public function get_maximum_tries() {
        $max = 1;
        foreach ($this->get_variant_nos() as $variantno) {
            foreach ($this->get_subpart_ids($variantno) as $subpartid) {
                $max = max($max, $this->get_analysis_for_subpart($variantno, $subpartid)->get_maximum_tries());
            }
        }
        return $max;
    }