src/vs/platform/contextkey/common/contextkey.ts/ContextKeyOrExpr/create
class ContextKeyOrExpr:	public static create(_expr: ReadonlyArray<ContextKeyExpression | null | undefined>): ContextKeyExpression | undefined {
		const expr = ContextKeyOrExpr._normalizeArr(_expr);
		if (expr.length === 0) {
			return undefined;
		}

		if (expr.length === 1) {
			return expr[0];
		}

		return new ContextKeyOrExpr(expr);
	}