apply

This function modifies the [class@Gtk.

TextTag] properties that are related to the Style properties. Other [ class@Gtk.TextTag] properties are left untouched.

If this is non-null, applies this to tag.

If this is null, the related *-set properties of [class@Gtk.TextTag] are set to false.

Parameters:

this	a Style to apply, or null.
tag	a TextTag to apply styles to.