src/vs/workbench/api/common/extHostNotebookDocument.ts/ExtHostNotebookDocument/_getCells
class ExtHostNotebookDocument:	private _getCells(range: vscode.NotebookRange): ExtHostCell[] {
		range = this._validateRange(range);
		const result: ExtHostCell[] = [];
		for (let i = range.start; i < range.end; i++) {
			result.push(this._cells[i]);
		}
		return result;
	}