public function getReceiver(TwitterOAuth $twitter)
    {
        if (is_int($this->to)) {
            return $this->to;
        }

        $user = $twitter->get('users/show', [
            'screen_name' => $this->to,
            'include_user_entities' => false,
            'skip_status' => true,
        ]);

        if ($twitter->getLastHttpCode() === 404) {
            throw CouldNotSendNotification::userWasNotFound($twitter->getLastBody());
        }

        return $user->id;
    }