changed data type

quoteli3.py

@@ -135,7 +135,7 @@ class QuoteLi3(datasets.GeneratorBasedBuilder):
                         context = self.get_context(quote, path)
                         answer_mention_start = context.find(search_text)
                         answer_mention_end = answer_mention_start + len(mention)
-                        if mention != 'NO_MENTION':
+                        if mention != 'NO_MENTION' and answer_mention_start >= 0:
                             answer_mention = {
                                 'answer': mention,
                                 'answer_start': answer_mention_start,