def get_ddG_results(self):
        """Parse the results from BuildModel and get the delta delta G's.

        A positive ddG means that the mutation(s) is destabilzing, negative means stabilizing.

            - highly stabilising (ΔΔG < −1.84 kcal/mol);
            - stabilising (−1.84 kcal/mol ≤ ΔΔG < −0.92 kcal/mol);
            - slightly stabilising (−0.92 kcal/mol ≤ ΔΔG < −0.46 kcal/mol);
            - neutral (−0.46 kcal/mol < ΔΔG ≤ +0.46 kcal/mol);
            - slightly destabilising (+0.46 kcal/mol < ΔΔG ≤ +0.92 kcal/mol);
            - destabilising (+0.92 kcal/mol < ΔΔG ≤ +1.84 kcal/mol);
            - highly destabilising (ΔΔG > +1.84 kcal/mol).

        Returns:
            dict: Dictionary of mutation group to predicted ddG.

        """
        foldx_avg_df = self.df_mutation_ddG_avg

        foldx_avg_ddG = {}
        results = foldx_avg_df[['Pdb', 'total energy', 'SD']].T.to_dict().values()
        for r in results:
            ident = r['Pdb'].split('_')[-1]
            ddG = r['total energy']
            ddG_sd = r['SD']

            foldx_avg_ddG[self.mutation_index_to_group[int(ident)]] = (ddG, ddG_sd)

        return foldx_avg_ddG