@@ -203,4 +203,4 @@ def abspath(self) -> PathLike:
         if self.repo.working_tree_dir is not None:
             return join_path_native(self.repo.working_tree_dir, self.path)
         else:
-            raise WorkTreeRepositoryUnsupported
+            raise WorkTreeRepositoryUnsupported("Working_tree_dir was None or empty")
@@ -4,6 +4,7 @@
 # This module is part of GitPython and is released under
 # the BSD License: http://www.opensource.org/licenses/bsd-license.php
 from mimetypes import guess_type
+from typing import Tuple, Union
 from . import base
 
 __all__ = ('Blob', )
@@ -23,7 +24,7 @@ class Blob(base.IndexObject):
     __slots__ = ()
 
     @property
-    def mime_type(self):
+    def mime_type(self) -> Union[None, Tuple[Union[None, str], Union[None, str]]]:
         """
         :return: String describing the mime type of this file (based on the filename)
         :note: Defaults to 'text/plain' in case the actual file type is unknown. """