docs: public double getDouble(String key) throws JSONException {
          Object object = this.get(key);
          try {
              return object instanceof Number ? ((Number) object).doubleValue()
                      : Double.parseDouble((String) object);
          } catch (Exception e) {
              throw new JSONException("JSONObject[" + quote(key)
                      + "] is not a number.");
          }
      }