Binding Keyboard Layout Swap to L_Shift+Alt

I recently formatted my Manjaro partition due to it getting corrupted. I used to have Keyboard Layout Swap bound to L_Shift+Alt via a command, however I can’t for the life of me figure out what command I used. I have tried to bind it via the GUI, but it needs an extra key that isn’t Alt or Shift (p.e. A). Can someone help?