def mount_options(self, options, device, mntpoint):
        if mntpoint == "/":
            self.root_mounted = True
        else:
            if not self.root_mounted:
                raise RuntimeError(
                    mntpoint % "mount: %s: No such file or directory")
        self.mounts.append((options, device, mntpoint))
dataset/ETHPy150Open BU-NU-CLOUD-SP16/Trusted-Platform-Module-nova/nova/tests/unit/virt/disk/vfs/fakeguestfs.py/GuestFS.mount_options/swapped operands of `%`