Adopt PEP 484 type hints for C++ types exported to Python
diff --git a/example/example-numpy-vectorize.ref b/example/example-numpy-vectorize.ref
index 4885fc1..d2d5d9b 100644
--- a/example/example-numpy-vectorize.ref
+++ b/example/example-numpy-vectorize.ref
@@ -76,3 +76,4 @@
 Int branch taken. 
 Float branch taken. 
 Complex float branch taken. 
+vectorized_func(arg0: numpy.ndarray[int], arg1: numpy.ndarray[float], arg2: numpy.ndarray[float]) -> object