TypeError: sequence item 0: expected str instance, bytes found

[drzraf]

ooktools wave clean --source ~/gqrx_20220327.wav -D test

Total Samples: 39563, Min: -16699, Max: 16701, Mean: 1.0
Cleaning up 39563 data points...
Normalizing values..
Writing output to file: test

Traceback (most recent call last):
[...]
  File "/usr/lib/python3/dist-packages/click/core.py", line 555, in invoke
    return callback(*args, **kwargs)
  File "/home/yug/.local/lib/python3.8/site-packages/ooktools/console.py", line 103, in clean
    converstions.clean_pwm_wave(**locals())
  File "/home/yug/.local/lib/python3.8/site-packages/ooktools/commands/converstions.py", line 75, in clean_pwm_wave
    output_wave.writeframes(''.join(frames))

ooktools v1.4, Python 3.8.10