def save_hdf(self, filename, path='', overwrite=False):
        """
        Saves PopulationSet to HDF file.
        """
        if os.path.exists(filename) and overwrite:
            os.remove(filename)

        for pop in self.poplist:
            name = pop.modelshort
            pop.save_hdf(filename, path='{}/{}'.format(path,name), append=True)
Saves PopulationSet to HDF file.