It looks like you must have accidentally deleted the "# " at the beginning of that line that makes it a comment. That means you’ve turned a sentence of English into python code, which (as we see) does not end well.
Here’s what that cell looks like in a clean version of this notebook:
available_copies = 4 ### DO NOT EDIT OR REMOVE THIS CODE LINE
### START CODE HERE ###
# 1. Reduce the number of "available_copies" by a value of 1
available_copies = # Add your code here
# 2. Print the message, confirming the checkout. Use multi-line f-string
# In your print statment, use "book_title" you implemented in exercise 1
# Use "available_copies" you calculated above
print(f"""
# Add your code here
""")
### END CODE HERE ###
Please compare that to what you are seeing in your notebook.
Yes, I was worried about that also, but I tried it both ways and either way passes the local test case and the final grader.
I also found at least one case in which you can actually fail the local test_your_code logic, but still pass the grader. Questions have been asked on the Mentor Forum.