code: def get_maps_stats(self):
          
          tpes = {}
          for m in self.maps:
              if m.tpe in tpes:
                  tpes[m.tpe] += 1
              else:
                  tpes[m.tpe] = 1
          return tpes
docs: calculates basic stats on the MapRule elements of the maps
          to give a quick overview.