diff --git a/product.py b/product.py
index 02205cefc8..2d7c468bba 100644
--- a/product.py
+++ b/product.py
@@ -20,6 +20,10 @@ class Configuration(metaclass=PoolMeta):
             "products.\n"
             "Used for products without a lead time."))
 
+    @classmethod
+    def default_default_lead_time(cls, **pattern):
+        return datetime.timedelta(0)
+
 
 class DefaultLeadTime(ModelSQL, CompanyValueMixin):
     "Product Default Lead Time"