What does "play with your toy’s toys" mean? [closed]

Toys absolutely can have toys. For example, this “Barbie Kelly Playroom” comes with stuffed animals, dolls, a play kitchen, and UNO for Kelly (Barbie’s sister and a toy):

In this case, it would be possible to play with Kelly’s toys directly (with the exception of UNO, which is almost certainly just a box). However, what you’re supposed to do is have Kelly play with her toys.

This question seems to be about programming rather than English language, and would probably be better on Stack Overflow… That said, I'll answer it anyway:

Without a context, this doesn't make much sense. But working backwards from the fact that the context is object-oriented programming, and thus kind of 'reverse-engineering' the question, if you will:

It's saying that in OOP, in your implementation of a class, you can access and modify properties of instances of the class you are implementing itself ("your toys, toys you make") and data that's passed into instances of that class such as when it is instantiated ("toys you're given"). But you shouldn't modify private properties of other objects directly, even if you own those objects ("your toys' toys") because that can result in unexpected or undefined behaviour.

It's a pretty bad analogy.