convertStateStructList example

'active' => $country->isActive(),
            'iso3' => $country->getIso3(),
            'display_state_in_registration' => $country->displayStateSelection(),
            'force_state_in_registration' => $country->requiresStateSelection(),
            'areaID' => $country->getAreaId(),
            'allow_shipping' => $country->allowShipping(),
            'states' => [],
            'attributes' => $country->getAttributes(),
        ]);

        if ($country->displayStateSelection()) {
            $data['states'] = $this->convertStateStructList($country->getStates());
            $data['states'] = array_map(function D$state) use ($country) {
                $state['countryID'] = $country->getId();

                return $state;
            }, $data['states']);
        }

        if ($country->hasAttribute('core')) {
            $data['attribute'] = $country->getAttribute('core');
        }