[pygame] Inventory items not working

[SheeppOSU]

I have this inventory for my game and I finally got buying items to work, but now any other items won't work. For example - I buy a weapon, now my other weapon does nothing when equipped. Also when trying to equip another weapon whilst one is already equipped, it is supposed to first ask the player to unequip the one currently equipped. TIA. game can be viewed/downloaded - https://github.com/Sheepposu/Destination - here