diff --git a/src/main/python/ddadevops/domain/release.py b/src/main/python/ddadevops/domain/release.py
index 8d57dfb..a639bd5 100644
--- a/src/main/python/ddadevops/domain/release.py
+++ b/src/main/python/ddadevops/domain/release.py
@@ -96,4 +96,4 @@ class Release():
         return result
 
     def is_valid(self, main_branch):
-        return self.validate(main_branch).count < 1
+        return len(self.validate(main_branch)) < 1