public function getGroups(Communicator $communicator = null): ClassValidationArray
    {
        if ($communicator !== null) {
            $groupsJSON = $communicator->get('api/contacts/'.$this->contactID. '/groups');
            $groupStd = json_decode($groupsJSON);
            $groups = RecipientFactory::createProcessedGroupsFromStdClassArray($groupStd);
            $this->groups = $groups;
            $this->fetchedGroups = true;
        }
        return $this->groups;
    }