code: def to_JSON(self):
          
          return json.dumps({'reference_time': self._reference_time,
                             'sunset_time': self._sunset_time,
                             'sunrise_time': self._sunrise_time,
                             'clouds': self._clouds,
                             'rain': self._rain,
                             'snow': self._snow,
                             'wind': self._wind,
                             'humidity': self._humidity,
                             'pressure': self._pressure,
                             'temperature': self._temperature,
                             'status': self._status,
                             'detailed_status': self._detailed_status,
                             'weather_code': self._weather_code,
                             'weather_icon_name': self._weather_icon_name,
                             'visibility_distance': self._visibility_distance,
                             'dewpoint': self._dewpoint,
                             'humidex': self._humidex,
                             'heat_index': self._heat_index})
docs: Dumps object fields into a JSON formatted string
  
          :returns: the JSON string