src/vs/workbench/contrib/notebook/common/notebookRange.ts/isICellRange
export function isICellRange(candidate: any): candidate is ICellRange {
	if (!candidate || typeof candidate !== 'object') {
		return false;
	}
	return typeof (<ICellRange>candidate).start === 'number'
		&& typeof (<ICellRange>candidate).end === 'number';
}