def reduce_object_file_names(self, dirn):
        """Recursively renames all files named XXX.cpython-...-linux-gnu.so"
        to "XXX.so", i.e. removing the erroneous architecture name
        coming from the local system.
        """
        py_so_files = shprint(sh.find, dirn, '-iname', '*.so')
        filens = py_so_files.stdout.decode('utf-8').split('\n')[:-1]
        for filen in filens:
            file_dirname, file_basename = split(filen)
            parts = file_basename.split('.')
            if len(parts) <= 2:
                continue
            shprint(sh.mv, filen, join(file_dirname, parts[0] + '.so'))