How do i re-render litelement component when object property's propert gets changed?

Let's say I have this property

content:{ 
type : Object, reflect : true, hasChanged(n,o){return true}}

and passing this object

values = {"a" : value : "somedata"}

I know that if I will change "values" it will re-render but how to get notified when I change values["a"].value = "nextdata";?