Solution Review: Mutable Nested Fields

type placeDetails = {
    house: string,
    mutable population: int
}
let placeDetails = {
  house: "Stark",
  population: 500000
};
type place = {
  name: string,
  placeDetails: placeDetails
};
let winterfell = {
  name: "Winterfell",
  placeDetails
};
winterfell.placeDetails.population = 100000;
Js.log(winterfell.placeDetails.population);