--- a/hgext/blackbox.py	Wed Aug 01 12:57:15 2018 -0700
+++ b/hgext/blackbox.py	Wed Aug 01 13:00:45 2018 -0700
@@ -45,6 +45,7 @@
 
 from mercurial import (
     encoding,
+    pycompat,
     registrar,
     ui as uimod,
     util,
@@ -111,7 +112,7 @@
             if st.st_size >= maxsize:
                 path = vfs.join(name)
                 maxfiles = ui.configint('blackbox', 'maxfiles')
-                for i in xrange(maxfiles - 1, 1, -1):
+                for i in pycompat.xrange(maxfiles - 1, 1, -1):
                     rotate(oldpath='%s.%d' % (path, i - 1),
                            newpath='%s.%d' % (path, i))
                 rotate(oldpath=path,