def METHOD_NAME(self, verb, *units):
    assert verb in ('enable', 'disable', 'mask')
    self.mkdir("/run/systemd/system")
    cmd = ['systemctl', '--root', self.tree, '--no-reload', verb]
    for unit in units:
        with contextlib.suppress(subprocess.CalledProcessError):
            args = cmd + [unit]
            self.runcmd(*args)