Custom media_player, defined async_ function in MediaPlayerDevice not found

Installation Home Assistant OS
1

Hi,

I am running Hass.io on Rpi 3. I modified a custom media_player component adding a new function ‘set_channel’ in webostv.py. I also defined in

media_player/init.py

in class

MediaPlayerDevice

and the two methods:

def set_channel(self, channel):
    """Set the TV channel ."""
    raise NotImplementedError()

def async_set_channel(self, channel):
    """Set the TV channel 'channel'.

    This method must be run in the event loop and returns a coroutine.
    """
    return self.hass.async_add_job(self.set_channel, channel)

At run time, calling the service set_chanell I get en error al this line:

        yield from getattr(player, method['method'])(**params)

HA is saying that no method ’ async_set_channel’ exists despite the above-mentioned definition.

Can some python/home assistant expert help me, please? I would like to be able to set the channel with name on my LGWebOs Tv.

Thank you very much!

Best regards,
Noro