Index: stack_data-0.6.2/tests/__init__.py
===================================================================
--- stack_data-0.6.2.orig/tests/__init__.py
+++ stack_data-0.6.2/tests/__init__.py
@@ -1,7 +1,7 @@
 import os
 
 import pyximport
-from typeguard.importhook import install_import_hook
+from typeguard import install_import_hook
 
 pyximport.install(language_level=3)
 
Index: stack_data-0.6.2/stack_data/utils.py
===================================================================
--- stack_data-0.6.2.orig/stack_data/utils.py
+++ stack_data-0.6.2/stack_data/utils.py
@@ -8,6 +8,11 @@ from typing import (
     TypeVar, Mapping,
 )
 
+try:
+    from types import NoneType
+except ImportError:
+    NoneType = type(None)
+
 from asttokens import ASTText
 
 T = TypeVar('T')
@@ -91,7 +96,7 @@ def is_frame(frame_or_tb: Union[FrameTyp
     return isinstance(frame_or_tb, (types.FrameType,))
 
 
-def iter_stack(frame_or_tb: Union[FrameType, TracebackType]) -> Iterator[Union[FrameType, TracebackType]]:
+def iter_stack(frame_or_tb: Union[FrameType, TracebackType, NoneType]) -> Iterator[Union[FrameType, TracebackType]]:
     while frame_or_tb:
         yield frame_or_tb
         if is_frame(frame_or_tb):