/**
  * Get a store context to use as the source of configuration.
  * @return Mage_Core_Model_Store
  */
 protected function _getSourceStore()
 {
     // this may return a Mage_Core_Model_Store or a Mage_Core_Model_Website
     $configSource = $this->_validatorHelper->getConfigSource($this->getRequest());
     // When given a website, get the default store for that website.
     // AMQP config is only at global and website level, so no *current*
     // possibility for the default store to have a different value than the website.
     if ($configSource instanceof Mage_Core_Model_Website) {
         return $configSource->getDefaultStore();
     }
     return $configSource;
 }