Question: what part of the mammary gland produces milk
[{'answer': 'cuboidal cells', 'provenance': [{'wikipedia_id': '311440', 'title': 'Mammary gland', 'start_paragraph_id': 3, 'start_character': 134, 'end_paragraph_id': 3, 'end_character': 148, 'bleu_score': 1.0, 'section': 'Section::::Structure.\n'}]}, {'provenance': [{'wikipedia_id': '311440', 'title': 'Mammary gland', 'start_paragraph_id': 3, 'start_character': 0, 'end_paragraph_id': 3, 'end_character': 637, 'bleu_score': 0.9806740509884301, 'meta': {'yes_no_answer': 'NONE', 'annotation_id': 14406554482354807614}, 'section': 'Section::::Structure.\n'}]}]