@@ -323,7 +323,7 @@ def traverse(self,      # type: ignore  # overrides super()
                     super(Tree, self).traverse(predicate, prune, depth,  # type: ignore
                                                branch_first, visit_once, ignore_self))
 
-    def list_traverse(self, *args: Any, **kwargs: Any) -> IterableList[Union['Tree', 'Submodule', 'Blob']]:
+    def list_traverse(self, *args: Any, **kwargs: Any) -> IterableList[IndexObjUnion]:
         return super(Tree, self).list_traverse(* args, **kwargs)
 
     # List protocol
 
@@ -19,13 +19,11 @@
 import calendar
 from datetime import datetime, timedelta, tzinfo
 
-from git.objects.base import IndexObject  # just for an isinstance check
-
 # typing ------------------------------------------------------------
 from typing import (Any, Callable, Deque, Iterator, NamedTuple, overload, Sequence,
                     TYPE_CHECKING, Tuple, Type, TypeVar, Union, cast)
 
-from git.types import Literal
+from git.types import Has_id_attribute, Literal
 
 if TYPE_CHECKING:
     from io import BytesIO, StringIO
@@ -319,7 +317,7 @@ def list_traverse(self, *args: Any, **kwargs: Any) -> IterableList[Union['Commit
         """
         # Commit and Submodule have id.__attribute__ as IterableObj
         # Tree has id.__attribute__ inherited from IndexObject
-        if isinstance(self, (TraversableIterableObj, IndexObject)):
+        if isinstance(self, (TraversableIterableObj, Has_id_attribute)):
             id = self._id_attribute_
         else:
             id = ""     # shouldn't reach here, unless Traversable subclass created with no _id_attribute_
 
@@ -11,9 +11,9 @@
     from git.repo import Repo
 
 if sys.version_info[:2] >= (3, 8):
-    from typing import Final, Literal, SupportsIndex, TypedDict, Protocol  # noqa: F401
+    from typing import Final, Literal, SupportsIndex, TypedDict, Protocol, runtime_checkable  # noqa: F401
 else:
-    from typing_extensions import Final, Literal, SupportsIndex, TypedDict, Protocol  # noqa: F401
+    from typing_extensions import Final, Literal, SupportsIndex, TypedDict, Protocol, runtime_checkable  # noqa: F401
 
 if sys.version_info[:2] >= (3, 10):
     from typing import TypeGuard  # noqa: F401
@@ -73,5 +73,11 @@ class HSH_TD(TypedDict):
     files: Dict[PathLike, Files_TD]
 
 
+@runtime_checkable
 class Has_Repo(Protocol):
     repo: 'Repo'
+
+
+@runtime_checkable
+class Has_id_attribute(Protocol):
+    _id_attribute_: str