public function getMemberships(Communicator $communicator = null): ClassValidationArray
    {
        if ($communicator !== null) {
            $membershipJSON = $communicator->get("api/groups/".$this->groupID."/memberships");
            $membershipStd = json_decode($membershipJSON);
            $memberships = [];
            foreach ($membershipStd as $value) {
                $memberships[] = RecipientFactory::createProcessedMembershipFromStdClass($value);
            }
            $this->memberships = $memberships;
            $this->fetchedMemberships = true;
        }
        return $this->memberships;
    }