import gi
gi.require_version('Gtk', '3.0')
from gi.repository import Gtk, Gio

def create_widget (item):
    print (item.get_label ())

    child = Gtk.FlowBoxChild ()
    child.add (item)

    return child

window = Gtk.Window ()
flowbox = Gtk.FlowBox ()
window.add (flowbox)

model = Gio.ListStore ()
flowbox.bind_model (model, create_widget)

item1 = Gtk.Label ("lala")
model.append (item1)

window.show_all ()
Gtk.main()

