/**
  * @param        $endPoint
  * @param string $apiVersion
  *
  * @return \BingAds\v10\Proxy\ClientProxy|\BingAds\v9\Proxy\ClientProxy
  */
 protected function _getClientProxy($endPoint, $apiVersion = BingAdsApi::VERSION_10)
 {
     if (isset($this->_clientProxies[$apiVersion][$endPoint])) {
         return $this->_clientProxies[$apiVersion][$endPoint];
     }
     return $this->_clientProxies[$apiVersion][$endPoint] = $this->_clientProxyFactory->createClientProxy($endPoint, $apiVersion);
 }