Merge pull request #9 from alafon/key-functions-not-private

Make it possible to call key functions when extending Dataloader

src/DataLoader.php

@@ -270,15 +270,24 @@ private static function awaitInstances()
         }
     }
 
-    private function getCacheKeyFromKey($key)
+    /**
+     * @param $key
+     *
+     * @return mixed
+     */
+    protected function getCacheKeyFromKey($key)
     {
         $cacheKeyFn = $this->options->getCacheKeyFn();
         $cacheKey = $cacheKeyFn ? $cacheKeyFn($key) : $key;
 
         return $cacheKey;
     }
 
-    private function checkKey($key, $method)
+    /**
+     * @param $key
+     * @param $method
+     */
+    protected function checkKey($key, $method)
     {
         if (null === $key) {
             throw new \InvalidArgumentException(