diff --git a/unittest/python/test_user_type.py b/unittest/python/test_user_type.py
index 8ae8cc12654351d4e61f15a043cd512ebd554783..83804208b22f995c8c8e2a086003eadf19b8c90b 100644
--- a/unittest/python/test_user_type.py
+++ b/unittest/python/test_user_type.py
@@ -5,7 +5,7 @@ rows = 10
 cols = 20
 
 def test(mat):
-  mat.fill(mat.dtype.type(10.))
+  mat[:] = mat.dtype.type(10.)
   mat_copy = mat.copy()
   assert (mat == mat_copy).all()
   assert not (mat != mat_copy).all()