diff --git a/slpkg/utilities.py b/slpkg/utilities.py
index b9451c6b..838f3023 100644
--- a/slpkg/utilities.py
+++ b/slpkg/utilities.py
@@ -35,7 +35,7 @@ class Utilities:
 
         return ''
 
-    def all_installed(self):
+    def all_installed(self) -> list:
         """ Return all installed SBo packages from /val/log/packages folder. """
         installed = []
         pattern = f'*{self.configs.sbo_repo_tag}'