Generate file paths to be excluded for namespace packages (bytecode
        cache files).

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(imp, 'get_tag'):
            return

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