Question: when do barney and robin first get together
[{'answer': 'Season 4', 'provenance': [{'wikipedia_id': '27412358', 'title': 'Barney Stinson', 'start_paragraph_id': 30, 'start_character': 675, 'end_paragraph_id': 30, 'end_character': 683, 'bleu_score': 1.0, 'section': 'Section::::Character.:Career.\n'}]}, {'provenance': [{'wikipedia_id': '27412358', 'title': 'Barney Stinson', 'start_paragraph_id': 41, 'start_character': 0, 'end_paragraph_id': 41, 'end_character': 1060, 'bleu_score': 0.9891594913313011, 'meta': {'yes_no_answer': 'NONE', 'annotation_id': 6953636252256056545}, 'section': 'Section::::Character.:Romantic relationships.:Robin Scherbatsky.\n'}]}]