diff --git a/product/ERP5Type/interfaces/cache_plugin.py b/product/ERP5Type/interfaces/cache_plugin.py
index dd8095eefa65b12ba4f62b219dfda931bc99c061..4c217d39ec82422da94fa4dc292d2e4143510eaa 100644
--- a/product/ERP5Type/interfaces/cache_plugin.py
+++ b/product/ERP5Type/interfaces/cache_plugin.py
@@ -57,7 +57,7 @@ class ICachePlugin(Interface):
   def get(cache_id, scope, default=None):
     """get the calculated value according to the cache_id and scope.
     raise KeyError if key does not exists and no default value provided.
-    return CacheEntry
+    return CacheEntry or default
     """
 
   def set(cache_id, scope, value, cache_duration=None, calculation_time=0):