Quarantine answer does not implement encode method

[Bobsans]

Example code:

async def _on_end_of_message(cmd: ppm.EndOfMessage) -> AbstractResponse:
    try:
        # process data
    except Exception as ex:
        logger.error(f'Unexpected error: {ex}', exc_info=True)

    return ppm.Quarantine(reason='Will be processed later')

And result is:
TypeError: Can't instantiate abstract class Quarantine with abstract method encode

By code also class Quarantine not implement method encode