guest@macbookair:~$ mate-power-manager

(mate-power-manager:574): Gtk-WARNING **: 08:35:25.674: Theme parsing error: gtk.css:51:14: not a number

(mate-power-manager:574): Gtk-WARNING **: 08:35:25.674: Theme parsing error: gtk.css:51:14: Expected a string.

(mate-power-manager:574): Gtk-WARNING **: 08:35:25.675: Theme parsing error: gtk.css:129:14: not a number

(mate-power-manager:574): Gtk-WARNING **: 08:35:25.675: Theme parsing error: gtk.css:129:14: Expected a string.

(mate-power-manager:574): Gtk-WARNING **: 08:35:25.679: Theme parsing error: gtk.css:845:21: not a number

(mate-power-manager:574): Gtk-WARNING **: 08:35:25.679: Theme parsing error: gtk.css:845:21: Expected a string.
TI:08:35:25 TH:0x55ef43ac5560   FI:gpm-main.c   FN:main,246
 - Power Manager is already running in this session.
Traceback:
    mate-power-manager(+0x19dff) [0x55ef433f0dff]
    mate-power-manager(+0x88a8) [0x55ef433df8a8]
    /lib/x86_64-linux-gnu/libc.so.6(__libc_start_main+0xe7) [0x7f2879566b97]
    mate-power-manager(+0x8b0a) [0x55ef433dfb0a]
guest@macbookair:~$