gtk:notebook-append-page (notebook child tab)

notebook -- a gtk:notebook widget
child -- the gtk:widget child to use as the content of the page
tab -- a gtk:widget object to use as the label for the page, or nil to use the default label, "page N"

An integer with the index starting from 0 of the appended page in the notebook, or -1 if the function fails.

Appends a page to the notebook.