In the Unitary Matrices 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!
I’ve checked, and it’s now solved. 
Hi @RezaNematpour , welcome to the Forum!
Thank you for reporting this issue and confirming that the issue is now resolved 
.
Feel free to open a new thread (or comment in an existing one) should you have any additional issues or questions!