diff --git a/tests/test_maybe/test_maybe_filter.py b/tests/test_maybe/test_maybe_filter.py
index d24bb7fb5..0254a3fd7 100644
--- a/tests/test_maybe/test_maybe_filter.py
+++ b/tests/test_maybe/test_maybe_filter.py
@@ -3,7 +3,7 @@
 
 def test_maybe_filter():
     """Ensures that .filter works correctly."""
-    def factory(argument: int) -> bool:
+    def factory(argument):
         return argument % 2 == 0
 
     assert Some(5).filter(factory) == Nothing