@Override
        public String toString() {
            StringBuilder sb = new StringBuilder();
            sb.append("{");
            int i = 0;
            Set<Map.Entry<String, String>> entries = this.entrySet();
            int size = entries.size();
            for (Map.Entry<String, String> entry : entries) {
                sb.append("\"");
                sb.append(entry.getKey());
                sb.append("\"");
                sb.append(":");
                sb.append("\"");
                sb.append(entry.getValue());
                sb.append("\"");
                sb.append(i + 1 < size ? "," : "");
                i++;
            }
            sb.append("}");
            return sb.toString();
        }