code: def set_ellipsoid(self, ellipsoid):
          
          if not isinstance(ellipsoid, (list, tuple)):
              try:
                  self.ELLIPSOID = ELLIPSOIDS[ellipsoid]
                  self.ellipsoid_key = ellipsoid
              except KeyError:
                  raise Exception(
                      "Invalid ellipsoid. See geopy.distance.ELIPSOIDS"
                  )
          else:
              self.ELLIPSOID = ellipsoid
              self.ellipsoid_key = None
          return
docs: Change the ellipsoid used in the calculation.