'QubitUnitary' object is not callable Error for codercise I.9.2

Codebook
1

In codercise I.9.2 in the Measurements Codebook challenge, I get
Error: 'QubitUnitary' object is not callable
when I run the correct code, or even when I run the provided starter code without any edits.
Looks like the issue happens inside the Codebook environment itself.

Thanks!

2

nevermind, it works now after I gave it a few minutes

3

This error usually happens when the Codebook environment’s kernel state gets out of sync, or if QubitUnitary was previously instantiated and accidentally called as a function in the workspace namespace. If starter code triggers it without any edits, restarting the Codebook kernel or refreshing the exercise session clears cached execution variables and fixes the issue.