eZ\Publish\Core\Limitation\UserGroupLimitationType::getCriterion PHP Method

    public function getCriterion(APILimitationValue $value, APIUserReference $currentUser)
    {
        if (empty($value->limitationValues)) {
            // no limitation values
            throw new \RuntimeException('$value->limitationValues is empty, it should not have been stored in the first place');
        }
        if ($value->limitationValues[0] != 1) {
            throw new BadStateException('Parent User Group limitation', 'expected limitation value to be 1 but got:' . $value->limitationValues[0]);
        }
        $groupIds = array();
        $currentUserLocations = $this->persistence->locationHandler()->loadLocationsByContent($currentUser->getUserId());
        if (!empty($currentUserLocations)) {
            foreach ($currentUserLocations as $currentUserLocation) {
                $groupIds[] = $currentUserLocation->parentId;
            }
        }
        return new Criterion\UserMetadata(Criterion\UserMetadata::GROUP, Criterion\Operator::IN, $groupIds);
    }