starting nameserver fails with "ValueError: can't have unbuffered text I/O"

[gerritholl]

Starting the nameserver in dæmon mode fails with Python 3.8.6, pytroll-collectors-0.10.0, and python-dæmon 2.2.4:

$ nameserver -d start -l /tmp/test.log
Traceback (most recent call last):
  File "/data/gholl/miniconda3/envs/py38b/bin/nameserver", line 129, in <module>
    angel = daemon.runner.DaemonRunner(APP)
  File "/data/gholl/miniconda3/envs/py38b/lib/python3.8/site-packages/daemon/runner.py", line 114, in __init__
    self._open_streams_from_app_stream_paths(app)
  File "/data/gholl/miniconda3/envs/py38b/lib/python3.8/site-packages/daemon/runner.py", line 134, in _open_streams_from_app_stream_paths
    self.daemon_context.stderr = open(
ValueError: can't have unbuffered text I/O

This is true while logging to a file or not.

Could this be a Python 2 / Python 3 issue?