diff --git a/examples/ellip_grating.py b/examples/ellip_grating.py
index a51a27e..57b170c 100644
--- a/examples/ellip_grating.py
+++ b/examples/ellip_grating.py
@@ -6,7 +6,7 @@ from masque.file import gdsii
 from masque import Arc, Pattern
 
 
-def main():
+def main() -> None:
     pat = Pattern()
     layer = (0, 0)
     pat.shapes[layer].extend([
diff --git a/examples/test_rep.py b/examples/test_rep.py
index f82575d..d25fb55 100644
--- a/examples/test_rep.py
+++ b/examples/test_rep.py
@@ -11,7 +11,7 @@ from masque.file import gdsii, dxf, oasis
 
 
 
-def main():
+def main() -> None:
     lib = Library()
 
     cell_name = 'ellip_grating'