1,​8-​Naphthyridine-​3-​carboxylic acid, 7-​[(1α,​5α,​6α)​-​6-​amino-​3-​azabicyclo[3.1.0]​hex-​3-​yl]​-​1-​(2,​4-​difluorophenyl)​-​6-​fluoro-​1,​4-​dihydro-​4-​oxo-