def get_package_data(package):
    """
    Return all files under the root package, that are not in a
    package themselves.
    """
    walk = [
        (dirpath.replace(package + os.sep, "", 1), filenames)
        for dirpath, dirnames, filenames in os.walk(package)
        if not os.path.exists(os.path.join(dirpath, "__init__.py"))
    ]

    filepaths = []
    for base, filenames in walk:
        filepaths.extend([os.path.join(base, filename) for filename in filenames])
    return {package: filepaths}

    Return all files under the root package, that are not in a
    package themselves.
    
setup.py