def _merge_result(self, command, res, **kwargs):
        """
        `res` is a dict with the following structure Dict(NodeName, CommandResult)
        """
        if command in self.result_callbacks:
            return self.result_callbacks[command](res, **kwargs)

        # Default way to handle result
        return first_key(res)
`res` is a dict with the following structure Dict(NodeName, CommandResult)