diff --git a/src/cutadapt/_handles.py b/src/cutadapt/_handles.py
index 778ff9d2..d5aa8b5a 100644
--- a/src/cutadapt/_handles.py
+++ b/src/cutadapt/_handles.py
@@ -12,11 +12,11 @@
 try:
     import msvcrt
 except ImportError:
-    msvcrt = None
+    msvcrt = None  # type: ignore
 try:
     import _winapi
 except ImportError:
-    _winapi = None
+    _winapi = None  # type: ignore
 
 
 class _PatchedDupHandle: