Control:SetAnchor() Clarification

[alfpogs]

I was wondering if anyone would be able to clear this up for me.

In the documentation for the Control class' SetAnchor() method on the wiki, it states the second parameter - anchorTargetControl - is simply an object.

Which type of object is that supposed to be? Is it an instance of a Control's anchor element, or of the Control itself, or something else? And what would be the best way to get that object?