Question: who is given credit for inventing the aqua lung
[{'answer': 'Émile Gagnan'}, {'answer': 'Jacques Cousteau'}, {'answer': 'engineer Émile Gagnan'}, {'answer': "Naval Lieutenant ( `` lieutenant de vaisseau '' ) Jacques Cousteau"}, {}, {'provenance': [{'wikipedia_id': '20548668', 'title': 'Aqua Lung/La Spirotechnique', 'section': 'Section::::History.\n', 'start_paragraph_id': 3, 'end_paragraph_id': 3, 'meta': {'evidence_span': ['In December 1942 the "lieutenant de vaisseau" (ship-of-the-Line Lieutenant) Jacques-Yves Cousteau met in Paris for the first time the engineer Émile Gagnan, employee at Air Liquide, a French company specialising in compressed gas. Because of severe fuel restrictions due to the German occupation of France, Gagnan had miniaturized and adapted to gas generators a Rouquayrol-Denayrouze-type regulator.', 'In December 1942 the "lieutenant de vaisseau" (ship-of-the-Line Lieutenant) Jacques-Yves Cousteau met in Paris for the first time the engineer Émile Gagnan, employee at Air Liquide, a French company specialising in compressed gas. Because of severe fuel restrictions due to the German occupation of France, Gagnan had miniaturized and adapted to gas generators a Rouquayrol-Denayrouze-type regulator', 'In December 1942 the "lieutenant de vaisseau" (ship-of-the-Line Lieutenant) Jacques-Yves Cousteau met in Paris for the first time the engineer Émile Gagnan, employee at Air Liquide, a French company specialising in compressed gas. Because of severe fuel restrictions due to the German occupation of France, Gagnan had miniaturized and adapted to gas generators a Rouquayrol-Denayrouze-type regulator. Invented in 1860, adapted to diving in 1864 and mass-produced as of 1865 (when the Ministry of the French Navy ordered the first apparati), the Rouquayrol-Denayrouze regulator was being commercialized in 1942 by the Bernard Piel Company, who had inherited the patent. Cousteau requested Gagnan to adapt his new own regulator to diving and both men patented in 1943 the first modern diving regulator.']}}]}]