It's my understanding that, at least in Python, you can't change immutable data type but you can just assign a new data to the same variable and therefore overwrite it, right? So even if JAX makes list type immutable, you can still just re-use `x` to save the new modified list.
We could indeed introduce syntactic sugar (`y= (x[0]:=10)` maybe), but you'll still need to introduce a new variable to hold the modified list.