diff -r 71443f742886 -r f64806207752 mercurial/worker.py
--- a/mercurial/worker.py	Thu Mar 11 21:07:04 2021 -0500
+++ b/mercurial/worker.py	Thu Mar 11 21:09:55 2021 -0500
@@ -104,7 +104,9 @@
 else:
 
     def ismainthread():
+        # pytype: disable=module-attr
         return isinstance(threading.current_thread(), threading._MainThread)
+        # pytype: enable=module-attr
 
     def _blockingreader(wrapped):
         return wrapped