I am overriding Usa\Model\Shipping\Carrier\Ups.php but its not working. i want update this function collectRates() code below

what's the problem

app/etc/modules/TechnikExpert_Usa.xml

true local

app\code\local\TechnikExpert\Usa\etc\config.xml

0.1 TechnikExpert_Usa_Model_Shipping_Carrier_Ups

app\code\local\TechnikExpert\Usa\Model\Shipping\Carrier\Ups.php

'https://onlinetools.ups.com/ups.app/xml/Rate', 'Track' => 'https://onlinetools.ups.com/ups.app/xml/Track', 'ShipConfirm' => 'https://onlinetools.ups.com/ups.app/xml/ShipConfirm', 'ShipAccept' => 'https://onlinetools.ups.com/ups.app/xml/ShipAccept', ); /** * Container types that could be customized for UPS carrier * * @var array */ protected $_customizableContainerTypes = array('CP', 'CSP'); /** * Collect and get rates * * @param Mage_Shipping_Model_Rate_Request $request * @return Mage_Shipping_Model_Rate_Result|bool|null */ public function collectRates(Mage_Shipping_Model_Rate_Request $request) { die('function called'); } }