public function minCosignatories($minCosignatories = null)
    {
        $minCosignatories = $minCosignatories ?: $this->getAttribute("minCosignatories") ?: $this->relativeChange;

        // "minCosignatories" can be used as direct attribute setter
        if (is_integer($minCosignatories)) {
            $relativeChange = $minCosignatories;
        }
        // "minCosignatories" is also a sub-dto
        elseif (is_array($minCosignatories) && isset($minCosignatories["relativeChange"])) {
            $relativeChange = $minCosignatories["relativeChange"];
        }
        else {
            $relativeChange = $this->relativeChange ?: 0;
        }

        $this->setAttribute("relativeChange", $relativeChange);
        return new Model(["relativeChange" => $this->relativeChange]);
    }