2 files changed, 3 insertions, 3 deletions

diff --git a/Mailman/Queue/Runner.py b/Mailman/Queue/Runner.py
index 3395314c6..e9cf4015a 100644
--- a/Mailman/Queue/Runner.py
+++ b/Mailman/Queue/Runner.py
@@ -210,7 +210,7 @@ class Runner:
 
         msgdata is a dictionary of message metadata.
         """
-        raise UnimplementedError
+        raise NotImplementedError
 
     def _doperiodic(self):
         """Do some processing `every once in a while'.
diff --git a/Mailman/Queue/Switchboard.py b/Mailman/Queue/Switchboard.py
index 478a1972e..6cc877a0a 100644
--- a/Mailman/Queue/Switchboard.py
+++ b/Mailman/Queue/Switchboard.py
@@ -181,10 +181,10 @@ class _Switchboard:
         return [times[k] for k in keys]
 
     def _ext_write(self, tmpfile, data):
-        raise UnimplementedError
+        raise NotImplementedError
 
     def _ext_read(self, dbfile):
-        raise UnimplementedError
+        raise NotImplementedError