Get dictionary representation of output arrays.

        Returns
        -------
        output_dict : dict of str to NDArray
            The dictionary that maps name of output names to NDArrays.

        Raises
        ------
        ValueError : if there are duplicated names in the outputs.

def output_dict(self):
        """Get dictionary representation of output arrays.

        Returns
        -------
        output_dict : dict of str to NDArray
            The dictionary that maps name of output names to NDArrays.

        Raises
        ------
        ValueError : if there are duplicated names in the outputs.
        """
        if self._output_dict is None:
            self._output_dict = Executor._get_dict(
                self._symbol.list_outputs(), self.outputs)
        return self._output_dict