def multiplicity(self):
        """
        Returns the multiplicity of a defect site within the structure (needed for concentration analysis)
        """
        sga = SpacegroupAnalyzer(self.bulk_structure)
        periodic_struc = sga.get_symmetrized_structure()
        poss_deflist = sorted(
            periodic_struc.get_sites_in_sphere(self.site.coords, 2, include_index=True), key=lambda x: x[1])
        defindex = poss_deflist[0][2]

        equivalent_sites = periodic_struc.find_equivalent_sites(self.bulk_structure[defindex])
        return len(equivalent_sites)