Update wikipedia-for-mask-filling.py

wikipedia-for-mask-filling.py

@@ -122,8 +122,8 @@ class WikipediaForMaskFilling(datasets.GeneratorBasedBuilder):
                     json_list = list(f)
                 
                 for json_str in json_list:
-                    example = json.loads(json_str)
-                    if example is not None and isinstance(example, dict):
+                    data = json.loads(json_str)
+                    if data is not None and isinstance(data, dict):
                         yield id_, {
                             "texts": data["texts"],
                             "masks": data["masks"]