Exception thrown when starting the tweak tool

[Mem2019]

gnome-tweak-tool WARNING : Shell not installed or running WARNING : Error detecting shell Traceback (most recent call last): File "/usr/lib/python2.7/dist-packages/gtweak/tweaks/tweak_group_shell_extensions.py", line 275, in init raise Exception("Shell not running or DBus service not available") Exception: Shell not running or DBus service not available WARNING : Shell not running None INFO : GSettings missing key org.gnome.nautilus.desktop (key computer-icon-visible)

The theme that I have installed is Arc-theme and its icon. However, there is no obvious influence. It is just the exception that makes me annoying, so I reported this. Thank you.