Get orbital projected Dos.

        Returns:
            dict of {orbital: Dos}, e.g. {"s": Dos object, ...}

def get_spd_dos(self):
        """
        Get orbital projected Dos.

        Returns:
            dict of {orbital: Dos}, e.g. {"s": Dos object, ...}
        """
        spd_dos = {}
        for atom_dos in self.pdos.values():
            for orb, pdos in atom_dos.items():
                orbital_type = _get_orb_type(orb)
                if orbital_type not in spd_dos:
                    spd_dos[orbital_type] = pdos
                else:
                    spd_dos[orbital_type] = \
                        add_densities(spd_dos[orbital_type], pdos)
        return {orb: Dos(self.efermi, self.energies, densities)
                for orb, densities in spd_dos.items()}