'Gets current parameters.
Returns
(arg_params, aux_params)
A pair of dictionaries each mapping parameter names to NDArray values. This
is a merged dictionary of all the parameters in the modules.'

def get_params(self):

    assert (self.binded and self.params_initialized)
    arg_params = dict()
    aux_params = dict()
    for module in self._modules:
        (arg, aux) = module.get_params()
        arg_params.update(arg)
        aux_params.update(aux)
    return (arg_params, aux_params)
