City: the Strongest Repairman

Liu Yun is a car mechanic, but he is a bit awesome as a mechanic. The performance of all cars repaired by him is improved by at least 10%, and can be tripled at most, achieving a qualitative leap. At first, everyone thought that Liu Yun could only repair cars, until one day, Liu Yun repaired robots, mobile phones, watches, airplanes, aircraft carriers, and even patients. Everyone was shocked and asked Liu Yun: "Is there anyone in this world that you can't cultivate?" "Probably... Not."