带有golang和gtk3的treeview

I use golang with gtk3

it works pretty

treeview :

tv, _ := gtk.TreeViewNew()
...
tvmodel,_ := tv.GetModel()
sel,_ := tv.GetSelection()
model,iter,ok := sel.GetSelected()

gives the selected node

to manage children :

nenf:=tvmodel.IterNChildren(iter)
var child gtk.TreeIter
for ind:=0; ind<nenf; ind++ {
    tvmodel.IterNthChild(&child,iter,ind)
    ...

it works

but how to find the parent ?

iterParent (or equivalent) seems not to exist