Question: when did the french join revolution on colonists side
[{'answer': '1778', 'provenance': [{'wikipedia_id': '2973792', 'title': 'France in the American Revolutionary War', 'start_paragraph_id': 1, 'start_character': 187, 'end_paragraph_id': 1, 'end_character': 191, 'bleu_score': 1.0, 'section': 'Section::::Abstract.'}]}, {'provenance': [{'wikipedia_id': '2973792', 'title': 'France in the American Revolutionary War', 'start_paragraph_id': 1, 'start_character': 0, 'end_paragraph_id': 1, 'end_character': 402, 'bleu_score': 0.9694566079002921, 'meta': {'yes_no_answer': 'NONE', 'annotation_id': 9395734300810373276}, 'section': 'Section::::Abstract.'}]}]