Question: who plays caleb rivers in pretty little liars
[{'answer': 'Tyler Blackburn', 'provenance': [{'wikipedia_id': '30974716', 'title': 'Tyler Blackburn', 'start_paragraph_id': 0, 'start_character': 0, 'end_paragraph_id': 0, 'end_character': 15, 'bleu_score': 1.0, 'section': 'Section::::Abstract.'}]}, {'provenance': [{'wikipedia_id': '30974716', 'title': 'Tyler Blackburn', 'start_paragraph_id': 1, 'start_character': 0, 'end_paragraph_id': 1, 'end_character': 200, 'bleu_score': 0.9419661180380051, 'meta': {'yes_no_answer': 'NONE', 'annotation_id': 3328460788804089286}, 'section': 'Section::::Abstract.'}]}]