diff --git a/libervia/backend/core/constants.py b/libervia/backend/core/constants.py
index e75d476c..0e6ebfcd 100644
--- a/libervia/backend/core/constants.py
+++ b/libervia/backend/core/constants.py
@@ -35,6 +35,9 @@ else:
     logged_user = getuser()
 
 
+bool_type = bool
+
+
 class Const(object):
 
     ## Application ##
@@ -455,13 +458,13 @@ class Const(object):
         )
 
     @classmethod
-    def bool(cls, value: str) -> bool:
+    def bool(cls, value: str) -> bool_type:
         """@return (bool): bool value for associated constant"""
         assert isinstance(value, str)
         return value.lower() in (cls.BOOL_TRUE, "1", "yes", "on", "y", "t")
 
     @classmethod
-    def bool_const(cls, value: bool) -> str:
+    def bool_const(cls, value: bool_type) -> str:
         """@return (str): constant associated to bool value"""
         assert isinstance(value, bool)
         return cls.BOOL_TRUE if value else cls.BOOL_FALSE