diff --git a/files/gvm_library.py b/files/gvm_library.py
index 000deefdfa5832003cbd13fc33e183d8a2285b16..60059d2acfd2b57f4909154bb8dce866320ac006 100644
--- a/files/gvm_library.py
+++ b/files/gvm_library.py
@@ -53,7 +53,7 @@ class PortList:
         return pretty_json(d)
     
     def __del__(self):
-        print("i'm going to delete port list: {self}")
+        print(f"i'm going to delete port list: {self}")
         self.delete()
         print("i finished to delete port list")