diff --git a/image_prediction/formatter/formatters/enum.py b/image_prediction/formatter/formatters/enum.py
index 55b8c18..bd9f27d 100644
--- a/image_prediction/formatter/formatters/enum.py
+++ b/image_prediction/formatter/formatters/enum.py
@@ -4,6 +4,9 @@ from image_prediction.formatter.formatters.key_formatter import KeyFormatter
 
 
 class EnumFormatter(KeyFormatter):
-    @staticmethod
-    def format_key(key):
+
+    def format_key(self, key):
         return key.value if isinstance(key, Enum) else key
+
+    def transform(self, obj):
+        raise NotImplementedError