Hi RyanLee
This confuses me since the error log shows the used python version is 3.7, which should support the unpacking of variables. Can you confirm that's the python version you are using. The *tl, *br should be completely valid syntactically.
EDIT: Uh, I see the problem, according to https://docs.python.org/3/whatsnew/3.8.html:
Generalized iterable unpacking in yield and return statements no longer requires enclosing parentheses. This brings the yield and return syntax into better agreement with normal assignment syntax:
Syntax is incorrect (not yet implemented) for python3.7, please use 3.8 or above.
Thanks,
Jaka