Question: when did trick or treating start in the us
[{'answer': 'the late 1920s'}, {'provenance': [{'wikipedia_id': '30861', 'title': 'Trick-or-treating', 'start_paragraph_id': 2, 'start_character': 0, 'end_paragraph_id': 2, 'end_character': 1247, 'bleu_score': 0.955797281362978, 'meta': {'yes_no_answer': 'NONE', 'annotation_id': 10866156107325405633}, 'section': 'Section::::Abstract.'}]}]