Question: who played mr thatcher in when calls the heart
[{'answer': 'Garwin Sanford', 'provenance': [{'wikipedia_id': '41630866', 'title': 'When Calls the Heart', 'start_paragraph_id': 28, 'start_character': 12, 'end_paragraph_id': 28, 'end_character': 26, 'bleu_score': 1.0, 'section': 'Section::::Cast.:Recurring.\n'}]}, {'provenance': [{'wikipedia_id': '41630866', 'title': 'When Calls the Heart', 'start_paragraph_id': 28, 'start_character': 0, 'end_paragraph_id': 28, 'end_character': 46, 'bleu_score': 0.6147881529512641, 'meta': {'yes_no_answer': 'NONE', 'annotation_id': 5270156013561006407}, 'section': 'Section::::Cast.:Recurring.\n'}]}, {'provenance': [{'wikipedia_id': '41630866', 'title': 'When Calls the Heart', 'start_paragraph_id': 0, 'start_character': 0, 'end_paragraph_id': 0, 'end_character': 0, 'bleu_score': 1.0, 'meta': {'yes_no_answer': 'NONE', 'annotation_id': 5270156013561006407}, 'section': 'Section::::Abstract.'}]}, {'provenance': [{'wikipedia_id': '41630866', 'title': 'When Calls the Heart', 'section': 'Section::::Cast.:Recurring.\n', 'start_paragraph_id': 28, 'end_paragraph_id': 28, 'meta': {'evidence_span': ['Garwin Sanford', 'Garwin Sanford as William Thatcher', 'BULLET::::- Garwin Sanford as William Thatcher']}}]}]