Method returning a dictionary of projections on elements and specific
        orbitals

        Args:
            el_orb_spec: A dictionary of Elements and Orbitals for which we want
                to have projections on. It is given as: {Element:[orbitals]},
                e.g., {'Cu':['d','s']}

        Returns:
            A dictionary of projections on elements in the
            {Spin.up:[][{Element:{orb:values}}],
            Spin.down:[][{Element:{orb:values}}]} format
            if there is no projections in the band structure returns an empty
            dict.

def get_projections_on_elements_and_orbitals(self, el_orb_spec):
        """
        Method returning a dictionary of projections on elements and specific
        orbitals

        Args:
            el_orb_spec: A dictionary of Elements and Orbitals for which we want
                to have projections on. It is given as: {Element:[orbitals]},
                e.g., {'Cu':['d','s']}

        Returns:
            A dictionary of projections on elements in the
            {Spin.up:[][{Element:{orb:values}}],
            Spin.down:[][{Element:{orb:values}}]} format
            if there is no projections in the band structure returns an empty
            dict.
        """
        result = {}
        structure = self.structure
        el_orb_spec = {get_el_sp(el): orbs for el, orbs in el_orb_spec.items()}
        for spin, v in self.projections.items():
            result[spin] = [[{str(e): collections.defaultdict(float)
                              for e in el_orb_spec}
                             for i in range(len(self.kpoints))]
                            for j in range(self.nb_bands)]

            for i, j, k in itertools.product(
                    range(self.nb_bands), range(len(self.kpoints)),
                    range(structure.num_sites)):
                sp = structure[k].specie
                for orb_i in range(len(v[i][j])):
                    o = Orbital(orb_i).name[0]
                    if sp in el_orb_spec:
                        if o in el_orb_spec[sp]:
                            result[spin][i][j][str(sp)][o] += v[i][j][
                                orb_i][k]
        return result