public function delete($listId, Subscriber $subscriber)
    {
        $subscriberHash = $this->mailchimp->subscriberHash($subscriber->getEmail());
        $result = $this->mailchimp->delete("lists/$listId/members/$subscriberHash");

        if (!$this->mailchimp->success()) {
            $this->throwMailchimpError($this->mailchimp->getLastResponse());
        }

        return $result;
    }