Get outputs of the previous forward computation.
        If begin or end is specified, return [begin, end)-th outputs,
        otherwise return all outputs.

        Parameters
        ----------
        merge_multi_context : bool
            Default is `True`. In the case when data-parallelism is used, the outputs
            will be collected from multiple devices. A `True` value indicate that we
            should merge the collected results so that they look like from a single
            executor.
        begin : int
            starting index of returned outputs in all outputs
        end : int or None
            ending index (excluded) of returned outputs.

        Returns
        -------
        If `merge_multi_context` is ``True``, it is like ``[out1, out2]``. Otherwise, it
        is like ``[[out1_dev1, out1_dev2], [out2_dev1, out2_dev2]]``. All the output
        elements are `NDArray`.

def get_outputs(self, merge_multi_context=True, begin=0, end=None):
        """Get outputs of the previous forward computation.
        If begin or end is specified, return [begin, end)-th outputs,
        otherwise return all outputs.

        Parameters
        ----------
        merge_multi_context : bool
            Default is `True`. In the case when data-parallelism is used, the outputs
            will be collected from multiple devices. A `True` value indicate that we
            should merge the collected results so that they look like from a single
            executor.
        begin : int
            starting index of returned outputs in all outputs
        end : int or None
            ending index (excluded) of returned outputs.

        Returns
        -------
        If `merge_multi_context` is ``True``, it is like ``[out1, out2]``. Otherwise, it
        is like ``[[out1_dev1, out1_dev2], [out2_dev1, out2_dev2]]``. All the output
        elements are `NDArray`.
        """
        if end is None:
            end = self.num_outputs
        outputs = [[exec_.outputs[i] for exec_ in self.execs]
                   for i in range(begin, end)]
        if merge_multi_context:
            outputs = _merge_multi_context(outputs, self.output_layouts)
        return outputs