How is an empty __init__.py file correct?

Empty files are perfectly fine:

The __init__.py files are required to make Python treat the directories as containing packages; this is done to prevent directories with a common name, such as string, from unintentionally hiding valid modules that occur later on the module search path. In the simplest case, __init__.py can just be an empty file, but it can also execute initialization code for the package or set the __all__ variable, described later.

Depending on what you plan to do it’s a good place to import public stuff from the modules in your package so people can simply use from yourpackage import whatever instead of having to use from yourpackage.somemodule import whatever.