This adds two extra elements, one unique identifier (in this case $this->objects, which ought to be definitely not be accessed anywhere else) and the key for that array.
To check whether the array has already been checked, just these extra elements are verified.
This adds two extra elements, one unique identifier (in this case $this->objects, which ought to be definitely not be accessed anywhere else) and the key for that array.
To check whether the array has already been checked, just these extra elements are verified.
At the end, these are removed again.