private static function getStockCodeParameter($testMode = 'false')
 {
     if ($testMode != 'true') {
         date_default_timezone_set("Australia/Sydney");
         //Limit of 100 at a time due to yahoo's url length limit
         $stockCodeList = Stock::whereNotIn('stock_code', Historicals::distinct()->where('date', date("Y-m-d"))->lists('stock_code'))->take(100)->lists('stock_code');
         $stockCodeParameter = "";
         foreach ($stockCodeList as $stockCode) {
             $stockCodeParameter .= "+" . $stockCode . ".AX";
         }
         return substr($stockCodeParameter, 1);
     } else {
         return "TLS.AX+CBA.AX";
     }
 }