How to use the radis.db.degeneracies.gi function in radis

dgb = df.groupby(by=['id', 'iso'])
        for (id, iso), idx in dgb.indices.items():
            _gs = gs(id, iso)
            if isinstance(_gs, tuple):
                # Molecules that have alternating degeneracy. 
                if id not in [2]: # CO2
                    raise NotImplementedError
                # normally we should find whether the rovibrational level is symmetric 
                # or asymmetric. Here we just assume it's symmetric, because 
                # CO2 asymmetric levels dont exist (gs=0) and they should not be
                # in the line database.
                _gs = _gs[0]
            
            dg = df.loc[idx]
            _gi = gi(id, iso)
            df.loc[idx, 'grotu'] = dg.gju * _gs * _gi
            df.loc[idx, 'grotl'] = dg.gjl * _gs * _gi
            
            if radis.DEBUG_MODE:
                assert (df.loc[idx, 'id'] == id).all()
                assert (df.loc[idx, 'iso'] == iso).all()
                


        # %%

        if dbformat in ['hitran', 'cdsd-hitemp', 'cdsd-4000']:
            # In HITRAN, AFAIK all molecules have a complete assignment of rovibrational
            # levels hence gvib=1 for all vibrational levels.
            #
            # Complete rovibrational assignment would not be True, for instance, for

def gi(self):
        from radis.db.degeneracies import gi
        I = self.isotope
        return gi(2, I)

def gi(self, ElecState):
        ''' Get state independant rotational degeneracy. Typically depends on the
        isotope

        See Also
        --------

        :func:`~radis.db.degeneracies.gi`
        '''
        from radis.db.degeneracies import gi
        M, I = ElecState.id, ElecState.iso
        return gi(M, I)