<SYSTEM_TASK:>
Solve the following problem using Python, implementing the functions described below, one line at a time
<END_TASK>
<USER_TASK:>
Description:
 def optimizer(self) -> Union[mx.optimizer.Optimizer, SockeyeOptimizer]: """ Returns the optimizer of the underlying module. """

        # TODO: Push update to MXNet to expose the optimizer (Module should have a get_optimizer method)
        return self.current_module._optimizer