Update masader.py

masader.py

@@ -105,6 +105,6 @@ class Masader(datasets.GeneratorBasedBuilder):
                 continue
 
             masader_entry = {col:entry_list[i] for i,col in enumerate(columns) if i != 2}
-            masader_entry['subsets'] = subsets
+            masader_entry['subsets'] = str(subsets)
             subsets = {}
             yield i, masader_entry