Hi, I have met the following bugs (Python version: 3.9.7). When I type the following code, it is complete fine. class ABC: a = 'a' b = [f'{a}'] However, when I write this code, it gives me error. Similar error happens not only for f-string, but also for addition of integer. class ABC: a = 'a' b = [f'{a}' for _ in range(1)] Traceback (most recent call last): File "C:\Users\user\AppData\Local\Temp/ipykernel_1384/2533654419.py", line 1, in <module> class ABC: File "C:\Users\user\AppData\Local\Temp/ipykernel_1384/2533654419.py", line 3, in ABC b = [f'{a}' for _ in range(1)] File "C:\Users\user\AppData\Local\Temp/ipykernel_1384/2533654419.py", line 3, in <listcomp> b = [f'{a}' for _ in range(1)] NameError: name 'a' is not defined Best, Hong