code: def __get_ws_distance(wstation, latitude, longitude):
      
      if wstation:
          try:
              wslat = float(wstation[__LAT])
              wslon = float(wstation[__LON])
  
              dist = vincenty((latitude, longitude), (wslat, wslon))
              log.debug("calc distance: %s (latitude: %s, longitude: "
                        "%s, wslat: %s, wslon: %s)", dist, latitude,
                        longitude, wslat, wslon)
              return dist
          except (ValueError, TypeError, KeyError):
              # value does not exist, or is not a float
              return None
      else:
          return None
docs: Get the distance to the weatherstation from wstation section of json.
  
      wstation: weerstation section of buienradar json (dict)
      latitude: our latitude
      longitude: our longitude