object-add-to-list

object-add-to-list is a compiled Lisp function in `eieio.el'.

(object-add-to-list OBJECT SLOT ITEM &optional APPEND)

In OBJECT's SLOT, add ITEM to the list of elements.
Optional argument APPEND indicates we need to append to the list.
If ITEM already exists in the list in SLOT, then it is not added.
Comparison is done with `equal' through the `member' function call.
If SLOT is unbound, bind it to the list containing ITEM.