diff --git a/digits/extensions/data/imageSegmentation/data.py b/digits/extensions/data/imageSegmentation/data.py
index fca14f4a1..3b0921f4d 100644
--- a/digits/extensions/data/imageSegmentation/data.py
+++ b/digits/extensions/data/imageSegmentation/data.py
@@ -220,7 +220,7 @@ def make_image_list(self, folder):
 
     def split_image_list(self, filelist, stage):
         if self.random_indices is None:
-            self.random_indices = range(len(filelist))
+            self.random_indices = list(range(len(filelist)))
             random.shuffle(self.random_indices)
         elif len(filelist) != len(self.random_indices):
             raise ValueError(