minor problem with ntpviz

ntpviz 
Traceback (most recent call last):
  File "/usr/local/bin/ntpviz", line 303, in <module>
    statlist = [NTPViz(statsdir=d, sitename=sitename) for d in statsdirs]
  File "/usr/local/bin/ntpviz", line 54, in __init__
    NTPStats.__init__(self, sitename, statsdir)
  File "/usr/local/lib/python2.7/dist-packages/ntpstats.py", line 39, in __init__
    line = gzip.open(logpart).readlines()
NameError: global name 'gzip' is not defined

$ git diff
diff --git a/ntpstats/ntpstats.py b/ntpstats/ntpstats.py
index 3edab1e..7fbe665 100644
--- a/ntpstats/ntpstats.py
+++ b/ntpstats/ntpstats.py
@@ -7,7 +7,7 @@ SPDX-License-Identifier: BSD-2-Clause
 
 from __future__ import print_function, division
 
-import os, sys, time, glob, calendar, subprocess, socket
+import os, sys, time, glob, calendar, subprocess, socket, gzip
 
 class NTPStats:
     "Gather statistics for a specified NTP site"

best regards Dave