diff --git a/lib/core/option.py b/lib/core/option.py
index dffa4c58c..e56e50cb0 100644
--- a/lib/core/option.py
+++ b/lib/core/option.py
@@ -913,7 +913,7 @@ def _setTamperingFunctions():
                     function()
 
             if not found:
-                errMsg = "missing function 'tamper(payload, headers)' "
+                errMsg = "missing function 'tamper(payload, **kwargs)' "
                 errMsg += "in tamper script '%s'" % tfile
                 raise SqlmapGenericException(errMsg)