def _gen_exclusion_paths():
        """
        Generate file paths to be excluded for namespace packages (bytecode
        cache files).
        """
        # always exclude the package module itself
        yield '__init__.py'

        yield '__init__.pyc'
        yield '__init__.pyo'

        if not hasattr(sys, 'implementation'):
            return

        base = os.path.join('__pycache__', '__init__.' + sys.implementation.cache_tag)
        yield base + '.pyc'
        yield base + '.pyo'
        yield base + '.opt-1.pyc'
        yield base + '.opt-2.pyc'

        Generate file paths to be excluded for namespace packages (bytecode
        cache files).
        
product/gradle-plugin/src/main/python/setuptools/command/install_lib.py