diff --git a/mandaye/server.py b/mandaye/server.py
index fcbcd0e..67a209f 100644
--- a/mandaye/server.py
+++ b/mandaye/server.py
@@ -77,7 +77,7 @@ def strize(v):
     '''Flatten unicode strings to str encoded as UTF-8'''
     if isinstance(v, unicode):
         return v.encode('utf-8')
-    if isinstance(v, [list, tuple]):
+    if isinstance(v, (list, tuple)):
         return type(v)([strize(e) for e in v])
     if isinstance(v, dict):
         return dict((strize(k), strize(e)) for k, e in v.iteritems())