Get the model by model_id

        Parameters
        ----------
        model_id : int
            model index
        
        Returns
        -------
        load_model : Graph
            the model graph representation

def load_model_by_id(self, model_id):
        """Get the model by model_id

        Parameters
        ----------
        model_id : int
            model index
        
        Returns
        -------
        load_model : Graph
            the model graph representation
        """

        with open(os.path.join(self.path, str(model_id) + ".json")) as fin:
            json_str = fin.read().replace("\n", "")

        load_model = json_to_graph(json_str)
        return load_model