Question: When did the battle occur for which William Johnstone Milne received the Victoria Cross?
{'answer': '9 to 12 April 1917', 'supporting_facts': [['William Johnstone Milne', 0], ['William Johnstone Milne', 1], ['William Johnstone Milne', 2], ['Battle of Vimy Ridge', 0], ['Battle of Vimy Ridge', 2]]}