The parent section is the section that contains this section. A special
case are sections of type GTK_CSS_SECTION_DOCUMENT. Their parent will
either be NULL if they are the original CSS document that was loaded by
gtk.css_provider.CssProvider.loadFromFile or a section of type
gtk.types.CssSectionType.Import if it was loaded with an import rule from
a different file.
Gets the parent section for the given section.
The parent section is the section that contains this section. A special case are sections of type GTK_CSS_SECTION_DOCUMENT. Their parent will either be NULL if they are the original CSS document that was loaded by gtk.css_provider.CssProvider.loadFromFile or a section of type gtk.types.CssSectionType.Import if it was loaded with an import rule from a different file.