Question: what were nato and warsaw pact examples of
[{'answer': 'a collective defence treaty', 'provenance': [{'wikipedia_id': '33622', 'title': 'Warsaw Pact', 'start_paragraph_id': 1, 'start_character': 100, 'end_paragraph_id': 1, 'end_character': 127, 'bleu_score': 1.0, 'section': 'Section::::Abstract.'}]}, {'provenance': [{'wikipedia_id': '33622', 'title': 'Warsaw Pact', 'start_paragraph_id': 1, 'start_character': 0, 'end_paragraph_id': 1, 'end_character': 735, 'bleu_score': 0.91188967970109, 'meta': {'yes_no_answer': 'NONE', 'annotation_id': 12465040325594685488}, 'section': 'Section::::Abstract.'}]}]