docs: def load_hdf(cls, filename, path=''):
          """
          Loads PopulationSet from file
          """
          with pd.HDFStore(filename) as store:
              models = []
              types = []
              for k in store.keys():
                  m = re.search('/(\S+)/stars', k)
                  if m:
                      models.append(m.group(1))
                      types.append(store.get_storer(m.group(0)).attrs.poptype)
          poplist = []
          for m,t in zip(models,types):
              poplist.append(t().load_hdf(filename, path='{}/{}'.format(path,m)))
  
          return cls(poplist)