How I can hide a module in Python?

Imagine the folowing folders:

• mymodule
  • internal
    • __init__.py
    • base.py
  • expose
    • __init__.py
    • classes.py
  • __init__.py

I want that when I type in my application:

from mymodule import 

Appears only the expose module.

What I should do to hide the module internal from import command?

Thanks for your help.