Error Messages

I’m Having A Small Issue In Python Where I’ll Do An Exercise Correctly, And It’ll Mark It Incorrect, But If I Move To The Previous Exercise And Go Back And Run It Again, It Shows As Correct. Do We Know Why This Happens?

The check mark is permanent unless you Reset the lesson. Once we complete an exercise we can play around with the code all we wish to experiment and study. Be sure you save your original work in a comment or on your local machine. If you Save Page As, your solution will be saved along with all the lesson material.