diff --git a/datasets/vision.py b/datasets/vision.py
index 0f156c1a..d8f6ee8d 100644
--- a/datasets/vision.py
+++ b/datasets/vision.py
@@ -7,7 +7,7 @@ class VisionDataset(data.Dataset):
     _repr_indent = 4
 
     def __init__(self, root, transforms=None, transform=None, target_transform=None):
-        if isinstance(root, torch._six.string_classes):
+        if isinstance(root, str):
             root = os.path.expanduser(root)
         self.root = root