diff --git a/lisa/tests/staging/utilclamp.py b/lisa/tests/staging/utilclamp.py
index 31455db9c92fa6c680cbd14c26b3ea5b5f830eb2..2c6d4cf9782ba63958148392aeb2c5dfd1645505 100644
--- a/lisa/tests/staging/utilclamp.py
+++ b/lisa/tests/staging/utilclamp.py
@@ -172,7 +172,7 @@ class UtilClamp(RTATestBundle, TestBundle):
 
         df_freq = self.trace.ana.frequency.df_cpus_frequency()
         df_freq = df_freq[['cpu', 'frequency']]
-        df_freq = df_freq.pivot(index=None, columns='cpu', values='frequency')
+        df_freq = df_freq.pivot(columns='cpu', values='frequency')
         df_freq.reset_index(inplace=True)
         df_freq.set_index('Time', inplace=True)