code: def most_rainy(self):
          
          max_rain = 0
          most_rainy = None
          for weather in self._forecast.get_weathers():
              d = weather.get_rain()
              if 'all' in d:
                  if d['all'] > max_rain:
                      max_rain = d['all']
                      most_rainy = weather
          return most_rainy
docs: Returns the *Weather* object in the forecast having the highest
          precipitation volume. The rain amount is retrieved via the
          ``get_rain['all']`` call; was the 'all' key missing for every *Weather*
          instance in the forecast,``None`` would be returned.
  
          :returns: a *Weather* object or ``None`` if no item in the forecast is
              eligible