Question: what season is when calls the heart on
[{'answer': 'sixth season', 'provenance': [{'wikipedia_id': '41630866', 'title': 'When Calls the Heart', 'start_paragraph_id': 3, 'start_character': 53, 'end_paragraph_id': 3, 'end_character': 65, 'bleu_score': 1.0, 'section': 'Section::::Abstract.'}]}]