code: func (ps *PageSetup) SetPaperSizeAndDefaultMargins(size *PaperSize) {
  	C.gtk_page_setup_set_paper_size_and_default_margins(ps.native(), size.native())
  }
docs: // SetPaperSizeAndDefaultMargins() is a wrapper around gtk_page_setup_set_paper_size_and_default_margins().