Allows to set volume. Should be value between 0..1.
        Returns the new volume.

def set_volume(self, volume):
        """ Allows to set volume. Should be value between 0..1.
        Returns the new volume.

        """
        volume = min(max(0, volume), 1)
        self.logger.info("Receiver:setting volume to %.1f", volume)
        self.send_message({MESSAGE_TYPE: 'SET_VOLUME',
                           'volume': {'level': volume}})
        return volume