To use the functions described in this section, you will need to load
the (gschem selection) module.
Each page in gschem has a selection associated with it,
which is some subset of the pages contents. Most actions in
gschem operate on the currently selected objects.
Returns ‘#t’ if object is in its containing page's selection. Otherwise, returns ‘#f’. If object is not in a
page, raises an ‘object-state’ error.Note: object must be directly included in a
page, not via inclusion in a componentobject.