src/vs/workbench/api/common/extHostNotebookKernels.ts/NotebookCellExecutionTask/validateAndConvertOutputs
class NotebookCellExecutionTask:	private validateAndConvertOutputs(items: vscode.NotebookCellOutput[]): NotebookOutputDto[] {
		return items.map(output => {
			const newOutput = NotebookCellOutput.ensureUniqueMimeTypes(output.items, true);
			if (newOutput === output.items) {
				return extHostTypeConverters.NotebookCellOutput.from(output);
			}
			return extHostTypeConverters.NotebookCellOutput.from({
				items: newOutput,
				id: output.id,
				metadata: output.metadata
			});
		});
	}