def build_package_data(self):
        """Copy data files into build directory"""
        for target, srcfile in self._get_package_data_output_mapping():
            self.mkpath(os.path.dirname(target))
            _outf, _copied = self.copy_file(srcfile, target)
            make_writable(target)
Copy data files into build directory
product/gradle-plugin/src/main/python/setuptools/command/build_py.py