etl: Add parameter to exercise placeholder to fix exercism#556

Mofeywalker · ilya-khadykin · commit 246d9ae5a2af · 2017-10-10T10:30:49.000+03:00
diff --git a/exercises/etl/etl.py b/exercises/etl/etl.py
@@ -1,2 +1,2 @@
-def transform():
+def transform(legacy_data):
 pass
