Hello @akshaylamba,
I don’t have the dataset and notebook in front of me.
If I remember correct, the notebook is not for “just executing”.
There are two cells above your problem:
In [260]: lnames = [labels_path+os.path.basename(fn)[:-4]+’_L.png’ for fn in fnames]
In [7]: lnames = [labels_path+os.path.basename(fn) for fn in fnames]
If I remember correct, you just have to execute the first one (thats the mask).
I think the second was a trail/error/visualisation thing.
As suggestion, look at the different input(images) and output (what is lnames / what is the shape after each cell).
As I’ve remember, you can face that problem more often in this notebook.
See Lesson 14 wiki