dmb.gnu open error fixed

app_utils/conf.py

@@ -22,7 +22,7 @@ class PersistentSettings(BaseModel):
         """
         Persist the pydantic-dict that represents the model
         """
-        with shelve.open("config.db") as db:
+        with shelve.open("config.db", flag="n", protocol=2) as db:
             db["settings"] = {**self.dict(), **data}