protected function getGenerator(array $handles)
    {
        foreach ($handles as $handle) {
            $handle->seek(0);
            while (false === $handle->eof()) {
                $string = str_replace(['\'', ' ', PHP_EOL, ','], '', $handle->fgets());

                if (false === strpos($string, '=>')) {
                    continue;
                }

                list($string, $pinyin) = explode('=>', $string);

                yield $string => $pinyin;
            }
        }
    }