Panasonic viera send key command

The panasonic viera pypi library allows sending any remote key press to the TV. It would be handy if this was exposed as a service.

The home assistant panasonic viera component already uses the remote to send keys. Any of the other keys could also be sent in this way (

This could be done as an additional service similar to how asyncpioneer allows extra features to the media player:

Pinging the current maintainer for thoughts/input: @joogps