Combine fields from the model in one Gtk.TreeViewColumn

I am not sure but I think it is possible to use more then one Gtk.CellRenderer in a Gtk.TreeViewColumn when using pack_start().

But I can't get it run and don't see what is wrong. The TreeView in this example code is empty.

#!/usr/bin/env python3
import random
import gi
gi.require_version('Gtk', '3.0')
from gi.repository import Gtk
from gi.repository import GLib

class TreeView(Gtk.TreeView):
    def __init__(self):
        # model
        self.model = Gtk.ListStore.new([int, int])
        for i in range(5):
            self.model.append([i, (i*10)])

        # view
        Gtk.TreeView.__init__(self, self.model)

        col = Gtk.TreeViewColumn.new()
        col.set_title('two model fields')

        self.rendererA = Gtk.CellRendererText()
        col.add_attribute(self.rendererA, 'text', 0)
        col.pack_end(self.rendererA, True)

        self.rendererB = Gtk.CellRendererText()
        col.add_attribute(self.rendererB, 'text', 1)
        col.pack_end(self.rendererB, True)

        self.append_column(col)

if __name__ == '__main__':
    win = Gtk.Window.new(0)
    win.view = TreeView()
    win.add(win.view)
    win.connect('destroy', Gtk.main_quit)
    win.show_all()
    Gtk.main()

And the Gtk-Warning is

(_col.py:22411): Gtk-CRITICAL **: 13:23:09.919: gtk_cell_area_attribute_connect: assertion 'gtk_cell_area_has_renderer (area, renderer)' failed

You did everything right except function order. Pack first, add_attribute second.