Frost supports first-class immutable types. All immutable types descend from the class frost.core.Immutable. By subclassing Immutable, you impose some restrictions on your class:

These restrictions combine to ensure that it is not possible to modify data in any instance of an immutable object. Immutable objects receive several benefits from this:

And, of course, there's always the obvious "it's easier to reason about things when they can't change out from under you" benefit.