In my case, I modify the stdout but the error was thrown by a third party (click lib), I need to overwrite the stdout because the program has a CLI and the locale env in the terminal seems to be wrong:
 codecs.lookup(locale.getpreferredencoding()).name == 'ascii'
 sys.getdefaultencoding() == 'utf-8'

For these cases I try to fix it forcing the the IO encoding to the value given by sys.getdefaultencoding(), otherwise the script in a CLI won't work properly. 

I can apply a monkey-patch on the third party method that return "os.get_terminal_size()" if a ValueError exception is thrown, actually, The script is working now with the monkey-patch, but I thought that a bit of more "magic" in get_terminal_size would help to deal with the encoding issues in python3 CLI programs.