Question: who plays mrs. walker on 13 reasons why
[{'answer': 'Brenda Strong', 'provenance': [{'wikipedia_id': '25247887', 'title': '13 Reasons Why', 'start_paragraph_id': 66, 'start_character': 363, 'end_paragraph_id': 66, 'end_character': 376, 'bleu_score': 1.0, 'section': 'Section::::Production.:Casting.\n'}]}, {'provenance': [{'wikipedia_id': '25247887', 'title': '13 Reasons Why', 'start_paragraph_id': 27, 'start_character': 0, 'end_paragraph_id': 27, 'end_character': 56, 'bleu_score': 0.7598356856515921, 'meta': {'yes_no_answer': 'NONE', 'annotation_id': 5881241888377277449}, 'section': 'Section::::Cast and characters.:Main.\n'}]}]