code: def loc_forecast(self, request, step, isotime=None):
          
          return json.loads(self._query(VAL, FORECAST, ALL, request, step, isotime).decode(errors="replace"))
docs: Return location-specific forecast data (including lists of available
          sites and time capabilities) for given time step.
          
          request:
              metoffer.SITELIST        Returns available sites
              metoffer.CAPABILITIES    Returns available times
              site ID, e.g. "3021"     Returns forecast data for site
              metoffer.ALL             Returns forecast data for ALL sites
          step:
              ""                       Step not required with SITELIST
                                       or CAPABILITIES
              metoffer.DAILY           Returns daily forecasts
              metoffer.THREE_HOURLY    Returns forecast for every three hours
          isotime:
              An ISO 8601 formatted datetime as string
                                       Returns only data for this time step.
                                       Possible time steps may be obtained
                                       through metoffer.CAPABILITIES