--- a/mercurial/tags.py	Thu Jan 16 13:34:04 2020 +0100
+++ b/mercurial/tags.py	Mon Feb 10 17:31:05 2020 -0500
@@ -720,7 +720,9 @@
 
         self._dirtyoffset = None
 
-        rawlentokeep = min(wantedlen, (rawlen / _fnodesrecsize) * _fnodesrecsize)
+        rawlentokeep = min(
+            wantedlen, (rawlen / _fnodesrecsize) * _fnodesrecsize
+        )
         if rawlen > rawlentokeep:
             # There's no easy way to truncate array instances. This seems
             # slightly less evil than copying a potentially large array slice.