diff --git a/lib/Tmdb/Model/Common/QueryParameter/Type/CollectionToCommaSeperatedString.php b/lib/Tmdb/Model/Common/QueryParameter/Type/CollectionToCommaSeperatedString.php
index 3ecb1413..05af7079 100644
--- a/lib/Tmdb/Model/Common/QueryParameter/Type/CollectionToCommaSeperatedString.php
+++ b/lib/Tmdb/Model/Common/QueryParameter/Type/CollectionToCommaSeperatedString.php
@@ -34,11 +34,6 @@ public function __construct(array $collection = array())
         }
     }
 
-    /**
-     * {@inheritdoc}
-     */
-    abstract public function getKey();
-
     /**
      * {@inheritdoc}
      */