serial.tools.miniterm fails with "'ascii' codec can't encode characters" on German Windows

[AndreKR]

> python -m serial.tools.miniterm

--- Available ports:
---  1: COM6                 Intel(R) Active Management Technology - SOL (COM6)
---  2: COM13                F5521gw Mobile Broadband Device Management (COM13)
---  3: COM14                F5521gw Mobile Broadband GPS Port (COM14)
Traceback (most recent call last):
  File "C:\Users\andre\.platformio\python27\Lib\runpy.py", line 174, in _run_module_as_main
    "__main__", fname, loader, pkg_name)
  File "C:\Users\andre\.platformio\python27\Lib\runpy.py", line 72, in _run_code
    exec code in run_globals
  File "C:\Users\andre\.platformio\penv\lib\site-packages\serial\tools\miniterm.py", line 930, in <module>
    main()
  File "C:\Users\andre\.platformio\penv\lib\site-packages\serial\tools\miniterm.py", line 857, in main
    args.port = ask_for_port()
  File "C:\Users\andre\.platformio\penv\lib\site-packages\serial\tools\miniterm.py", line 325, in ask_for_port
    sys.stderr.write('--- {:2}: {:20} {}\n'.format(n, port, desc))
UnicodeEncodeError: 'ascii' codec can't encode characters in position 9-10: ordinal not in range(128)

The next COM port that would follow is called Standardmäßgige Seriell-über-Bluetooth-Verbindung, so I guess the ä and ß is to blame here.