public static function &getInstance()
 {
     if (self::$_instance === null) {
         self::$_instance = new self();
     }
     return self::$_instance;
 }
 /**
  * 获取二手房那天城市价格
  * @param $data
  * @return bool|mixed|null
  */
 public function getSalePrice($cityId, $startDate, $status = 1)
 {
     $tmpPrice = Model_Broker_EntrustPriceSale::getInstance()->getCityPrice($cityId, $startDate, $status);
     if (!empty($tmpPrice)) {
         return intval($tmpPrice->discountPrice);
     } else {
         return 0;
     }
 }