diff --git a/slpkg/utilities.py b/slpkg/utilities.py
index 473a5821..b76b4fc3 100644
--- a/slpkg/utilities.py
+++ b/slpkg/utilities.py
@@ -113,7 +113,7 @@ class Utilities:
         return [f for f in flag if f in flags]
 
     @staticmethod
-    def read_packages_from_file(file) -> Generator:
+    def read_packages_from_file(file: str) -> Generator:
         """ Reads packages from file and split these to list. """
         try: