/**
  * Legt einen neuen Request an und speichert die Parent/Child Relation
  * @param array|null $param
  * @return Request
  */
 public function createSubRequest($param = null)
 {
     $newRequest = new Request($param);
     $newRequest->setParentRequest($this);
     $newRequest->hash = $this->hash;
     $this->subRequests[] = $newRequest;
     return $newRequest;
 }