src/vs/workbench/contrib/notebook/browser/notebookEditorDecorations.ts/NotebookRefCountedStyleSheet/constructor
class NotebookRefCountedStyleSheet:	constructor(readonly widget: { removeEditorStyleSheets: (key: string) => void; }, key: string, styleSheet: HTMLStyleElement) {
		this._key = key;
		this._styleSheet = styleSheet;
		this._refCount = 0;
	}