src/vs/workbench/contrib/notebook/browser/view/cellParts/codeCell.ts/CodeCell/registerDecorations
class CodeCell:	private registerDecorations() {
		// Apply decorations
		this._register(this.viewCell.onCellDecorationsChanged((e) => {
			e.added.forEach(options => {
				if (options.className) {
					this.templateData.rootContainer.classList.add(options.className);
				}

				if (options.outputClassName) {
					this.notebookEditor.deltaCellContainerClassNames(this.viewCell.id, [options.outputClassName], []);
				}
			});

			e.removed.forEach(options => {
				if (options.className) {
					this.templateData.rootContainer.classList.remove(options.className);
				}

				if (options.outputClassName) {
					this.notebookEditor.deltaCellContainerClassNames(this.viewCell.id, [], [options.outputClassName]);
				}
			});
		}));

		this.viewCell.getCellDecorations().forEach(options => {
			if (options.className) {
				this.templateData.rootContainer.classList.add(options.className);
			}

			if (options.outputClassName) {
				this.notebookEditor.deltaCellContainerClassNames(this.viewCell.id, [options.outputClassName], []);
			}
		});
	}