diff --git a/lib/client/gnt_node.py b/lib/client/gnt_node.py
index 1819a0de7305c22e4d6fdad83111efc6d97c22ee..86d277db78ac531e98c7eda60c04772ea6d3e55c 100644
--- a/lib/client/gnt_node.py
+++ b/lib/client/gnt_node.py
@@ -211,7 +211,7 @@ def ListNodes(opts, args):
   selected_fields = ParseFields(opts.output, _LIST_DEF_FIELDS)
 
   fmtoverride = dict.fromkeys(["pinst_list", "sinst_list", "tags"],
-                              (lambda value: ",".join(value), False))
+                              (",".join, False))
 
   return GenericList(constants.QR_NODE, selected_fields, args, opts.units,
                      opts.separator, not opts.no_headers,