Cast keys recursively including iterables (issue 1639 syntax error)

gluon/serializers.py

@@ -47,20 +47,23 @@ def cast_keys(o, cast=str, encoding="utf-8"):
             newobj = dict()
         else:
             newobj = Storage()
-
         for k, v in o.items():
             if (cast == str) and isinstance(k, unicode):
                 key = k.encode(encoding)
             else:
                 key = cast(k)
-            if isinstance(v, (dict, Storage)):
-                value = cast_keys(v, cast=cast, encoding=encoding)
-            else:
-                value = v
-            newobj[key] = value
+            newobj[key] = cast_keys(v, cast=cast, encoding=encoding)
+    elif isinstance(o, (tuple, set, list)):
+        newobj = []
+        for item in o:
+            newobj.append(cast_keys(item, cast=cast, encoding=encoding))
+        if isinstance(o, tuple):
+            newobj = tuple(newobj)
+        elif isinstance(o, set):
+            newobj = set(newobj)
     else:
-        raise TypeError("Cannot cast keys: %s is not supported" % \
-                        type(o))
+        # no string cast (unknown object)
+        newobj = o
     return newobj
 
 def loads_json(o, unicode_keys=True, **kwargs):