Failed to store audio setting on the system with mono audio channel

Description:
Failed to parse the audio volume on the system with audio mono channel.
The scripts would raise an AttributeError as following:
Traceback (most recent call last):
  File "/tmp/nest-0tcihe6t.3361f09f54625130ca8353599d2d0b04ec843608119aba04070f3a0948f151e7/audio_settings.py", line 9, in <module>
    sys.exit(main())
  File "/usr/lib/python3/dist-packages/checkbox_support/scripts/audio_settings.py", line 368, in main
    store_audio_settings(settings_file)
  File "/usr/lib/python3/dist-packages/checkbox_support/scripts/audio_settings.py", line 237, in store_audio_settings
    volume = int(volume_regex.search(entry).group(1).strip())
AttributeError: 'NoneType' object has no attribute 'group'

Here is the audio data through pactl command
Cmd> pactl list sources
...
Source #2
State: RUNNING
Name: alsa_input.usb-C-Media_Electronics_Inc._Cmedia_Audio-00.analog-mono
Description: Cmedia Audio Analog Mono
Driver: module-alsa-card.c
Sample Specification: s24le 1ch 48000Hz
Channel Map: mono
Owner Module: 8
Mute: no
Volume: mono: 42967 / 66% / -11.00 dB
        balance 0.00