Question: when did california become part of the usa
[{'answer': 'January 13 , 1847', 'provenance': [{'wikipedia_id': '5407', 'title': 'California', 'start_paragraph_id': 28, 'start_character': 462, 'end_paragraph_id': 28, 'end_character': 479, 'bleu_score': 1.0, 'section': 'Section::::History.:California Republic and American invasion.\n'}]}, {'provenance': [{'wikipedia_id': '5407', 'title': 'California', 'start_paragraph_id': 28, 'start_character': 0, 'end_paragraph_id': 28, 'end_character': 519, 'bleu_score': 0.9346183847893801, 'meta': {'yes_no_answer': 'NONE', 'annotation_id': 10382740768120461113}, 'section': 'Section::::History.:California Republic and American invasion.\n'}]}]