* added optional argument to command service
* Fixed crash when optional argument is not provided
* Updated argument description
* fixed lint error
* Fix isort error
* switched to use dict for optional field instead of json string
* switched to use ATTR_PAYLOAD
* fixed test
* actually fixed test
* Add yamllint (in pre-commit and CI)
* Fix linting for all YAML files
* Bump and add it to requirements
* Fix gen_requirements for pre-commit, remove 'v' from version
* Webostv: add sound_output capability
Add the ability to read and set the sound_output
* Webostv: add sound_output capability
* Webostv: add sound_output capability
* fix blank spaces
* fix to long line
* add ,
* Import ATTR_SOUND_OUTPUT
Do not have the ability to test this change right now
* Add white space
* Create const.py
* Use const import
* Use import from const.py
* Add docstring
* Change order
* Change order
* Fix import
* Fix import
* Fix typo
* Change order again
* Change order again
* Change order of attributes