diff --git a/tools/kvm/kvm_stat/kvm_stat b/tools/kvm/kvm_stat/kvm_stat
index 5898c22ba310bdf27f626a2dfb7bc45e5cf2a505..645d4bb69f5fa5b02d391c124babe4a242f7ae62 100755
--- a/tools/kvm/kvm_stat/kvm_stat
+++ b/tools/kvm/kvm_stat/kvm_stat
@@ -1134,12 +1134,14 @@ class Tui(object):
         def get_sorted_events(self, stats):
             """ separate parent and child events """
             if self._sorting == SORT_DEFAULT:
-                def sortkey((_k, v)):
+                def sortkey(pair):
                     # sort by (delta value, overall value)
+                    v = pair[1]
                     return (v.delta, v.value)
             else:
-                def sortkey((_k, v)):
+                def sortkey(pair):
                     # sort by overall value
+                    v = pair[1]
                     return v.value
 
             childs = []