public function getContacts(Communicator $communicator = null): ClassValidationArray
    {
        if ($communicator !== null) {
            $contactStd = $communicator->get('api/groups/'.$this->groupID. '/contacts');
            $contactStd = json_decode($contactStd);
            $contacts = RecipientFactory::createProcessedGroupsFromStdClassArray($contactStd);
            $this->contacts = $contacts;
            $this->contactsFetched = true;
        }
        return $this->contacts;
    }