diff --git a/pytools/__init__.py b/pytools/__init__.py
index 62fc22e9..8cbb1f2b 100644
--- a/pytools/__init__.py
+++ b/pytools/__init__.py
@@ -37,7 +37,7 @@
 from sys import intern
 from typing import (cast,
     Any, Callable, ClassVar, Dict, Generic, Hashable, Iterable, Iterator, List,
-    Mapping, Optional, Sequence, Set, Tuple, Type, TypeVar, Union)
+    Mapping, Optional, Sequence, Set, Tuple, Type, TypeVar, Union, cast)
 
 
 try:
diff --git a/run-mypy.sh b/run-mypy.sh
index cb7227d0..2115e48c 100755
--- a/run-mypy.sh
+++ b/run-mypy.sh
@@ -4,4 +4,4 @@ set -ex
 
 mypy pytools
 
-mypy --strict pytools/datatable.py
+mypy --strict --follow-imports=skip pytools/datatable.py