CURA-5330 Fix typing in the Backups

cura/API/Backups.py

@@ -1,5 +1,7 @@
 # Copyright (c) 2018 Ultimaker B.V.
 # Cura is released under the terms of the LGPLv3 or higher.
+from typing import Tuple, Optional
+
 from cura.Backups.BackupsManager import BackupsManager
 
 
@@ -17,7 +19,7 @@ class Backups:
     ##  Create a new back-up using the BackupsManager.
     #   \return Tuple containing a ZIP file with the back-up data and a dict
     #   with metadata about the back-up.
-    def createBackup(self) -> (bytes, dict):
+    def createBackup(self) -> Tuple[Optional[bytes], Optional[dict]]:
         return self.manager.createBackup()
 
     ##  Restore a back-up using the BackupsManager.

cura/Backups/BackupsManager.py

@@ -1,6 +1,6 @@
 # Copyright (c) 2018 Ultimaker B.V.
 # Cura is released under the terms of the LGPLv3 or higher.
-from typing import Optional
+from typing import Optional, Tuple
 
 from UM.Logger import Logger
 from cura.Backups.Backup import Backup
@@ -18,7 +18,7 @@ class BackupsManager:
     ##  Get a back-up of the current configuration.
     #   \return A tuple containing a ZipFile (the actual back-up) and a dict
     #   containing some metadata (like version).
-    def createBackup(self) -> (Optional[bytes], Optional[dict]):
+    def createBackup(self) -> Tuple[Optional[bytes], Optional[dict]]:
         self._disableAutoSave()
         backup = Backup()
         backup.makeFromCurrent()