def _get_module_mapping(self) -> Iterator[Tuple[str, str]]:
        """Iterate over all modules producing (dest, src) pairs."""
        for package, module, module_file in self.find_all_modules():
            package = package.split('.')
            filename = self.get_module_outfile(self.build_lib, package, module)
            yield (filename, module_file)
Iterate over all modules producing (dest, src) pairs.
product/gradle-plugin/src/main/python/setuptools/command/build_py.py