MultiFile Add-on with single python file [duplicate]

I am making an add-on in blender that has one python file. In the past, I have been able to just import this add-on as a single python file by itself, but I need to use a .zip file for this because my add-on needs a .blend file to work. I have tried installing my current add-on as a zip with files as so:

addon.zip:

Please see the included add-ons that come with Blender as examples. If you are on Windows, that will most likely be C:\Program Files\Blender Foundation\Blender [version number]\[version number]\scripts\addons\ If you go to any of the folders there, you will see what would be in the zip file if it was a zipped addon:
The main addon file is __init__.py, you have to have one like that.