private function prepareMail($notifiable)
 {
     $mail = new MailMessage();
     $data = ['recipient' => $notifiable];
     if ($title = $this->title($notifiable)) {
         $data['title'] = $title;
     }
     if ($this->subject) {
         $mail->subject($this->subject);
         $data['subject'] = $this->subject;
     }
     if (is_array($additionalData = $this->data($notifiable))) {
         foreach ($additionalData as $name => $value) {
             $data[$name] = $value;
         }
     }
     $mail->view($this->view, $data);
     return $mail;
 }