Issue #18200: Update the stdlib (except tests) to use
ModuleNotFoundError.
diff --git a/Lib/socketserver.py b/Lib/socketserver.py
index e9e4e4e..a6ee718 100644
--- a/Lib/socketserver.py
+++ b/Lib/socketserver.py
@@ -136,7 +136,7 @@
 import errno
 try:
     import threading
-except ImportError:
+except ModuleNotFoundError:
     import dummy_threading as threading
 
 __all__ = ["TCPServer","UDPServer","ForkingUDPServer","ForkingTCPServer",