/**
  * Duplicate back refs
  *
  * @param CMbObject $object         Object to duplicate back refs of
  * @param string    $backname       Back reference name
  * @param string    $fwd_field      Forward field name
  * @param mixed     $fwd_value      Forward field value
  * @param array     $exclude_fields Excluded fields
  *
  * @return void
  */
 private function duplicateBackRefs(CMbObject $object, $backname, $fwd_field, $fwd_value, $exclude_fields = array())
 {
     $new = null;
     foreach ($object->loadBackRefs($backname) as $_back) {
         /** @var CMbObject $_back */
         $this->duplicateObject($_back, $fwd_field, $fwd_value, $new, $exclude_fields);
     }
 }