
The error "UnicodeDecodeError: 'utf-8' codec can't decode byte 0xbf in position 108: invalid start byte" means there are some letters Python cannot read in the file. I found those letters in your file.cio file and deleted them then it seems working now.
I attached a modified one. Try with this and let me know if you still have the same issue.
Thanks,
Seonggyu