Well I peeked at the solution, and I see that the problem was I hadn’t wrapped df.info() in a print statement. But why did the error appear the way the way it did? How does the missing print statement mess up the memory usage in some invisible way?
It doesn’t mess up the memory usage. Our answer checking here could be more refined than what it is. As of the time when you experienced this, the answer checker expects None to be printed and you didn’t print it. It’s stupid to print it, though, your answer should be considered correct and our answer needs to be fixed.
Because it’s checking the differences between your output and Dataquest’s expected output.