--- a/mercurial/help.py Fri Mar 03 13:32:10 2017 -0500
+++ b/mercurial/help.py Wed Mar 08 18:31:33 2017 -0500
@@ -618,6 +618,8 @@
"""
if keep is None:
keep = []
+ else:
+ keep = list(keep) # make a copy so we can mutate this later
fullname = name
section = None
subtopic = None