gobject:define-gobject-subclass (gname name (&key superclass export interfaces) (&rest properties))

gname -- a string for the new g:type-t name of the subclass
name -- a Lisp symbol for the name of the new subclass
keywords -- valid keywords are :superclass, :export and :interfaces
:superclass -- a Lisp type specifier for the superclass
:export -- a boolean whether to export the subclass symbols
:interfaces -- a List for the g:type-t names of the interfaces for the subclass
properties -- a list for the properties of the new subclass

This macro defines a new subclass from superclass.