docs: public JSONObject increment(String key) throws JSONException {
          Object value = opt(key);
          if (value == null) {
              put(key, 1);
          }
          else if (value instanceof Integer) {
              put(key, ((Integer)value).intValue() + 1);
          }
          else if (value instanceof Long) {
              put(key, ((Long)value).longValue() + 1);
          }
          else if (value instanceof Double) {
              put(key, ((Double)value).doubleValue() + 1);
          }
          else if (value instanceof Float) {
              put(key, ((Float)value).floatValue() + 1);
          }
          else {
              throw new JSONException("Unable to increment [" + key + "].");
          }
          return this;
      }