gsettings set org.gnome.desktop.wm.keybindings switch-input-source "['<Shift>Alt_L']"
gsettings set org.gnome.desktop.wm.keybindings switch-input-source-backward "['<Alt>Shift_L']"
gsettings set org.gnome.desktop.wm.keybindings switch-input-source "['<Alt>Shift_L']"
set get
<Primary>space, Alt_R, <Shift>Control_R, <Shift><Super>space