How to create my own ex command in AstroNvim, nvim, macOS

I want to add ex command to AstroNvim so that when i type

:rn

it does:

:!python3 path_to_current_file

so that i could save some typing, if rn command already does something then rename it to :rnf or :rncf

I asked chatGPT and bingAI, but they gave me different responses every time I asked. I also searched it up but did not found answer, my ~/.config directory looks like that if it helps:

 .config├── init.lua├── lazy-lock.json├── lua│├── community.lua│├── lazy_setup.lua│├── plugins││├── astrocore.lua││├── astrolsp.lua││├── astroui.lua││├── mason.lua││├── myplugs.lua││├── none-ls.lua││├── treesitter.lua││└── user.lua│└── polish.lua├── neovim.yml├── README.md└── selene.toml