Core: adds a custom KeyError for invalid item names (#4223)

* adds a custom KeyError for raising on world.create_item() if the passed in name is invalid

* Update __init__.py

---------

Co-authored-by: Exempt-Medic <60412657+Exempt-Medic@users.noreply.github.com>

worlds/AutoWorld.py

@@ -22,6 +22,10 @@ if TYPE_CHECKING:
 perf_logger = logging.getLogger("performance")
 
 
+class InvalidItemError(KeyError):
+    pass
+
+
 class AutoWorldRegister(type):
     world_types: Dict[str, Type[World]] = {}
     __file__: str

worlds/generic/__init__.py

@@ -3,7 +3,7 @@ import logging
 
 from BaseClasses import Item, Tutorial, ItemClassification
 
-from ..AutoWorld import World, WebWorld
+from ..AutoWorld import InvalidItemError, World, WebWorld
 from NetUtils import SlotType
 
 
@@ -47,7 +47,7 @@ class GenericWorld(World):
     def create_item(self, name: str) -> Item:
         if name == "Nothing":
             return Item(name, ItemClassification.filler, -1, self.player)
-        raise KeyError(name)
+        raise InvalidItemError(name)
 
 
 class PlandoItem(NamedTuple):