You are an expert in writing code in many different languages. Your goal is to perform code completion for the following code, keeping in mind the rest of the code and the file meta data.
    Metadata details:
    filename: e006.rs
    path of file: ./repos/newrustacean.com/src
    
    the code of the file until where you have to start completion: //! Modularize this!
//!
//!   - **Date:** November 16, 2015
//!   - **Subject:
    
pub fn use_modules_internal() {
    println!("At `use_modules_internal()`.");

    // Calling another module's function is quite straightforward.
    internal_module::a_public_module_fn();

    // Note that we cannot access the internal module's private function. If you
    // uncomment the following line, you will see a compile error indicating
    // that the function is private.
    //
    //     internal_module::a_private_module_fn();
    //
    // Similarly, as you would expect, we have access to public functions in
    // public modules, but no access to private functions in public modules. (We
    // have already seen this, in fact, just in file-based, rather than
    // declaration-based, modules.)
    public_internal_module::a_public_module_fn();
}