diff --git a/tests/python_client/chaos/chaos_commons.py b/tests/python_client/chaos/chaos_commons.py
index c0e325e3ba..af00a20c75 100644
--- a/tests/python_client/chaos/chaos_commons.py
+++ b/tests/python_client/chaos/chaos_commons.py
@@ -9,13 +9,13 @@ from utils.util_log import test_log as log
 
 def check_config(chaos_config):
     if not chaos_config.get('kind', None):
-        raise Exception("kind is must be specified")
+        raise Exception("kind must be specified")
     if not chaos_config.get('spec', None):
-        raise Exception("spec is must be specified")
+        raise Exception("spec must be specified")
     if "action" not in chaos_config.get('spec', None):
-        raise Exception("action is must be specified in spec")
+        raise Exception("action must be specified in spec")
     if "selector" not in chaos_config.get('spec', None):
-        raise Exception("selector is must be specified in spec")
+        raise Exception("selector must be specified in spec")
     return True