Can't use oomox with pywal

[ghost]

Long story short, i want to generate gtk theme with oomox. I tried the solution here: https://linuxconfig.org/how-to-customize-your-gtk-desktop-with-oomox-and-pywal But it didn't work. Here is the output:

usage: wal [-h] [-a "alpha"] [-b background] [--backend [backend]] [--theme [/path/to/file or theme_name]] [--iterative] [--saturate 0.0-1.0]
           [--preview] [--vte] [-c] [-i "/path/to/img.jpg"] [-l] [-n] [-o "script_name"] [-q] [-r] [-R] [-s] [-t] [-v] [-e]
wal: error: unrecognized arguments: -g /home/rev/Wallpaper/sakura-tree.png

Can someone help me with this? Thanks.