island: Extract old data dir manipulation to a separate function

monkey/monkey_island/cc/server_setup.py

@@ -5,7 +5,7 @@ import shutil
 import sys
 from pathlib import Path
 from threading import Thread
-from typing import Tuple
+from typing import Optional, Tuple
 
 import gevent.hub
 from gevent.pywsgi import WSGIServer
@@ -71,12 +71,18 @@ def _setup_data_dir(island_args: IslandCmdArgs) -> Tuple[IslandConfigOptions, st
         print(f"Error loading server config: {ex}")
         exit(1)
     except OldDataError as ex:
+        return _handle_existing_data_directory(ex, island_args)
+
+
+def _handle_existing_data_directory(
+    exception: Exception, island_args: IslandCmdArgs
+) -> Optional[Tuple[IslandConfigOptions, str]]:
     user_response = input(
-            f"\nExisting data directory ({ex.old_data_dir}) needs to be deleted."
+        f"\nExisting data directory ({exception.old_data_dir}) needs to be deleted."
         " All data from previous runs will be lost. Proceed to delete? (y/n) "
     )
     if user_response == "y":
-            shutil.rmtree(ex.old_data_dir)
+        shutil.rmtree(exception.old_data_dir)
         print("\nOld data directory was deleted. Trying to set up again...\n")
         return _setup_data_dir(island_args)
     elif user_response == "n":