docs: def nearest_loc_forecast(self, lat, lon, step):
          """
          Work out nearest possible site to lat & lon coordinates
          and return its forecast data for the given time step.
          
          lat:                        float or int.  Latitude.
          lon:                        float or int.  Longitude.
          step:
              metoffer.DAILY          Returns daily forecasts
              metoffer.THREE_HOURLY   Returns forecast for every three hours
          """
          sitelist = self.loc_forecast(SITELIST, step)
          sites = parse_sitelist(sitelist)
          site = get_nearest_site(sites, lat, lon)
          return self.loc_forecast(site, step)