体验 SphereEx-Boot时，在安装 demo 集群这个步骤出现了一个问题，请教一下如何解决。用的是在线安装的方式。
异常信息：
copying shell file
The task includes an option with an undefined variable. The error was: ‘dict object’ has no attribute ‘shell_file_dir’The error appears to be in ‘/root/.spex/clusters/demo/proxy-play.yaml’: line 23, column 5, but may
be elsewhere in the file depending on the exact syntax problem.The offending line appears to be:
dest: '{{ item.install_dir }}'
- name: proxy_copy_shell_files
^ here