diff --git a/worlds/Files.py b/worlds/Files.py
index b569344081..b5ff6097d4 100644
--- a/worlds/Files.py
+++ b/worlds/Files.py
@@ -41,7 +41,7 @@ class AutoPatchRegister(abc.ABCMeta):
 
 class AutoPatchExtensionRegister(abc.ABCMeta):
     extension_types: ClassVar[Dict[str, AutoPatchExtensionRegister]] = {}
-    required_extensions: ClassVar[Tuple[str, ...]] = ()
+    required_extensions: Tuple[str, ...] = ()
 
     def __new__(mcs, name: str, bases: Tuple[type, ...], dct: Dict[str, Any]) -> AutoPatchExtensionRegister:
         # construct class
@@ -374,7 +374,7 @@ class APPatchExtension(metaclass=AutoPatchExtensionRegister):
     Patch extension functions must return the changed bytes.
     """
     game: str
-    required_extensions: List[str] = []
+    required_extensions: ClassVar[Tuple[str, ...]] = ()
 
     @staticmethod
     def apply_bsdiff4(caller: APProcedurePatch, rom: bytes, patch: str):