Question: when did kai kai and jia jia come to singapore
[{'answer': 'September 2012', 'provenance': [{'wikipedia_id': '29164215', 'title': 'River Safari', 'start_paragraph_id': 12, 'start_character': 643, 'end_paragraph_id': 12, 'end_character': 657, 'bleu_score': 1.0, 'section': 'Section::::Attractions.:Giant pandas.\n'}]}, {'provenance': [{'wikipedia_id': '29164215', 'title': 'River Safari', 'start_paragraph_id': 12, 'start_character': 0, 'end_paragraph_id': 12, 'end_character': 692, 'bleu_score': 0.9196785619188741, 'meta': {'yes_no_answer': 'NONE', 'annotation_id': 13999076078499276266}, 'section': 'Section::::Attractions.:Giant pandas.\n'}]}]