src/vs/base/browser/ui/list/listView.ts/ListViewAccessibilityProvider/constructor
class ListViewAccessibilityProvider:	constructor(accessibilityProvider?: IListViewAccessibilityProvider<T>) {
		if (accessibilityProvider?.getSetSize) {
			this.getSetSize = accessibilityProvider.getSetSize.bind(accessibilityProvider);
		} else {
			this.getSetSize = (e, i, l) => l;
		}

		if (accessibilityProvider?.getPosInSet) {
			this.getPosInSet = accessibilityProvider.getPosInSet.bind(accessibilityProvider);
		} else {
			this.getPosInSet = (e, i) => i + 1;
		}

		if (accessibilityProvider?.getRole) {
			this.getRole = accessibilityProvider.getRole.bind(accessibilityProvider);
		} else {
			this.getRole = _ => 'listitem';
		}

		if (accessibilityProvider?.isChecked) {
			this.isChecked = accessibilityProvider.isChecked.bind(accessibilityProvider);
		} else {
			this.isChecked = _ => undefined;
		}
	}