/**
  * Fetch object based on array of properties.
  *
  * @param array $params
  *   (reference ) an assoc array of name/value pairs.
  * @param array $defaults
  *   (reference ) an assoc array to hold the flattened values.
  *
  * @return CRM_Core_BAO_WebTracking
  */
 public static function retrieve(&$params, &$defaults)
 {
     $webtracking = new CRM_WebTracking_BAO_WebTracking();
     $webtracking->copyValues($params);
     if ($webtracking->find(TRUE)) {
         CRM_Core_DAO::storeValues($webtracking, $defaults);
         return $webtracking;
     }
     return NULL;
 }