$ showco cable-test --help
usage: showco cable-test [-h] [STR] [STR] [--duration-seconds FLOAT] [--mixers-config PATH]

Test X18 analog cables between AUX sends and inputs

 positional arguments
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  [STR]                     channels (default: 9-14)
  [STR]                     sends (default: 1-6)

 options
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  -h, --help                show this help message and exit
  --duration-seconds FLOAT  (default: 3.0)
  --mixers-config PATH      (default: /Users/tom/.config/showco/mixers.toml)
