[pygame] Inventory problems. Weapons equipped to wrong slot

[SheeppOSU]

I've been working on this inventory for so long. i finally made big progress on it but I have a problem.

Problem - When buying an item it is successfully put into inventory. The only problem is that it takes the original weapon. The original weapon is still there but does nothing when being equipped. Instead, the new weapon takes equips the original weapon.

I have my code in github here - https://github.com/Sheepposu/Destination - It can also be installed and tested for visual purposes. All the pictures should be updated into the picture folder. TIA for your help