@Override // ISidedInventory
 public boolean canExtractItem(int slot, ItemStack stack, int side) {
   switch (slot) {
     case SLOT_IMPORT:
     default:
       return false;
     case SLOT_EXPORT:
       return ItemHelper.itemsIdentical(_inventory.getExport(), stack);
   }
 }
 @Override
 public boolean equals(Object o) {
   if (o == null || !Key.class.isAssignableFrom(o.getClass())) return false;
   return ItemHelper.itemsIdentical(_stack, ((Key) o).stack());
 }