chalk (something) up to experience

To regard a bad situation, action, or outcome as a learning experience rather than dwelling on its negative impact. I know you're upset about failing your exam, but just chalk it up to experience and try harder next time! Try not to dwell on this loss. The best thing you can do is chalk it up to experience and move on. I know this has been a whole debacle, but you can chalk it up to experience and never work with these people again.