/**
  * update a Segment
  *
  * @param Segment $segment
  * @return Segment
  */
 public function updateSegment(Segment $segment)
 {
     // convert the object to the array that will transform into json
     $content = array('type' => $segment->type, 'id' => $segment->id, 'name' => $segment->name, 'description' => $segment->description, 'creation' => Field::getFormatDate(strtotime($segment->creation_date)), 'expiration' => Field::getFormatDate(strtotime($segment->expiration_date)), 'isTest' => $segment->for_test);
     list($this->last_result, $this->last_error) = $this->rest_client->put($this->path . '/' . $segment->id, $content);
     $this->erreur = $this->getError($this->last_result, $this->last_error);
     if (isset($this->erreur)) {
         return null;
     }
     if (!Segment::isJsonValid($this->last_result)) {
         $this->erreur = $this->jsonErrorMessage();
         return null;
     }
     return new Segment($this->last_result);
 }