def METHOD_NAME(self, channel_names, attr_name, output, ctrls):
    """ Get the same channel attribute across multiple devices
        which are assumed to be strings
    """
    if not isinstance(channel_names, list):
        channel_names = [channel_names]
    return {
        ctrl.name: [
            self._get_iio_attr_str(chan_name, attr_name, output, ctrl)
            for chan_name in channel_names
        ]
        for ctrl in ctrls
    }