public function emailsComeFromListOfApprovedSenders($emailAddress) {

        // are we checking that inbound emails come from a pre-approved list of senders?
        if (!$this->isInboundEmailsFromAllowedSendersOnly()) {

            // we are *not* checking that emails come from a pre-approved list of senders
            return true;
        }

        // yes, we are checking that emails come from a pre-approved list of senders
        if ($this->isInboundEmailsFromAllowedSendersOnlyListOfSsenders($emailAddress)) {

            // the sender is, indeed, on the list of pre-approved senders
            return true;
        }

        // the sender is not on the list of pre-approved senders
        return false;
    }