/**
  * Get cache key.
  *
  * @return string
  */
 protected function getCacheKey()
 {
     return parent::getCacheKey() . '.currencylayer';
 }
 /**
  * Get cache key.
  *
  * @return string
  */
 protected function getCacheKey()
 {
     return parent::getCacheKey() . '.openexchangerates';
 }