/**
  * @param SignatureRequestRecipient $recipient
  * @return array recipient creation result
  */
 public function addRecipient(SignatureRequestRecipient &$recipient)
 {
     $response = $recipient->create();
     if (isset($response['recipients'])) {
         $recipients = $this->formRecipients($response['recipients']);
         $newRecipient = array_diff_key($recipients, $this->recipients);
         $this->recipients = $recipients;
         $result = array_pop($newRecipient);
         $recipient = $result;
         return true;
     }
     return $response;
 }
<?php

use PDFfiller\OAuth2\Client\Provider\SignatureRequestRecipient;
$provider = (require_once __DIR__ . '/../bootstrap/initWithFabric.php');
$e = SignatureRequestRecipient::one($provider, 129498, 136835)->remind();
dd($e);