Update poquad.py

poquad.py

@@ -111,7 +111,7 @@ class SquadV2(datasets.GeneratorBasedBuilder):
 
                         answer_starts = [answer["answer_start"] for answer in qa["answers"]]
                         answers = [answer["text"] for answer in qa["answers"]]
-                        is_impossible = qa["is_impossible"]
+                        is_impossible = question["is_impossible"]
                         # Features currently used are "context", "question", and "answers".
                         # Others are extracted here for the ease of future expansions.
                         id_ += 1