src/vs/workbench/contrib/notebook/common/notebookRange.ts/cellRangesToIndexes
export function cellRangesToIndexes(ranges: ICellRange[]) {
	const indexes = ranges.reduce((a, b) => {
		for (let i = b.start; i < b.end; i++) {
			a.push(i);
		}

		return a;
	}, [] as number[]);

	return indexes;
}