def bindmount(self, mountpoint):

        if not self.mountpoint:
            return False
        try:
            self.bindmountpoint = mountpoint
            _util.check_call_(['mount', '--bind', self.mountpoint, self.bindmountpoint], stdout=subprocess.PIPE)
            return True
        except Exception as e:
            self.bindmountpoint = ""
            logger.exception("Error bind mounting {0}.".format(self))
            return False
Return the key string in the form of:
dataset/ETHPy150Open ralphje/imagemounter/imagemounter/volume.py/Volume.bindmount--crossover with--dataset/ETHPy150Open saltstack/salt/salt/key.py/RaetKey._get_key_str