diff --git a/taskflow/states.py b/taskflow/states.py
index a06187b4..28272cd3 100644
--- a/taskflow/states.py
+++ b/taskflow/states.py
@@ -46,7 +46,7 @@ EXECUTE = 'EXECUTE'
 IGNORE = 'IGNORE'
 REVERT = 'REVERT'
 RETRY = 'RETRY'
-INTENTIONS = [EXECUTE, IGNORE, REVERT, RETRY]
+INTENTIONS = (EXECUTE, IGNORE, REVERT, RETRY)
 
 # Additional engine states
 SCHEDULING = 'SCHEDULING'