/**
  * Reset the instance of select that is used in the select method if part is not set
  * Reset the defined part in the select if part is set
  *
  * @param string $part
  */
 public function reset($part = null)
 {
     if ($part) {
         $this->select->reset($part);
     } else {
         $this->select = null;
     }
     return $this;
 }