Question: where is hcl secreted in the digestive system
[{'answer': 'the lumen of the stomach', 'provenance': [{'wikipedia_id': '638449', 'title': 'Gastric acid', 'start_paragraph_id': 3, 'start_character': 359, 'end_paragraph_id': 3, 'end_character': 383, 'bleu_score': 1.0, 'section': 'Section::::Abstract.'}]}, {'provenance': [{'wikipedia_id': '638449', 'title': 'Gastric acid', 'start_paragraph_id': 3, 'start_character': 0, 'end_paragraph_id': 3, 'end_character': 661, 'bleu_score': 0.9817332376369081, 'meta': {'yes_no_answer': 'NONE', 'annotation_id': 479190358865110263}, 'section': 'Section::::Abstract.'}]}]