Update the connector information for a given model.

        Returns None if the specified model not exist.

        Parameters
        ----------
        model_id : string
            Unique model identifier
        connector : dict
            New connection information

        Returns
        -------
        ModelHandle

def update_model_connector(self, model_id, connector):
        """Update the connector information for a given model.

        Returns None if the specified model not exist.

        Parameters
        ----------
        model_id : string
            Unique model identifier
        connector : dict
            New connection information

        Returns
        -------
        ModelHandle
        """
        # Validate the given connector information
        self.validate_connector(connector)
        # Connector information is valid. Ok to update the model.
        return self.registry.update_connector(model_id, connector)