>>> with_x_y( ['You', 'flagged', 'a', 'taxi', 'ride', 'Let', 'down', 'your', 'expectations', 'Of', 'a', 'different', 'night'] ) == 't' True >>> with_x_y( ['Noble', 'gases:', 'helium,', 'neon,', 'argon,', 'krypton,', 'xenon,', 'radon,', 'oganesson'] ) == 'k' True >>> len(with_x_y( ['The', 'letters', 'we', 'search', 'for', 'are', 'not', 'around', 'in', 'this', 'case'] )) 0 >>> with_x_y( ['The', 'Girl', 'with', 'the', 'Flaxen', 'Hair', 'by', 'Debussy'] ) == 'F' True