code: def _get_area_rates(self, source, mmin, mmax=np.inf):
          
          points = list(source)
          for point in points:
              self._get_point_rates(point, mmin, mmax)
docs: Adds the rates from the area source by discretising the source
          to a set of point sources
  
          :param source:
              Area source as instance of :class:
              openquake.hazardlib.source.area.AreaSource