Adds a guide to layout.
A guide can be used as the source or target of constraints, like a widget, but it is not visible.
The layout acquires the ownership of guide after calling this function.
a gtk.constraint_guide.ConstraintGuide object
Adds a guide to layout.
A guide can be used as the source or target of constraints, like a widget, but it is not visible.
The layout acquires the ownership of guide after calling this function.