PyGTK how to pass a Liststore row value to another class in another python file

Question

In Glade, I created a Liststore that shows me a list of people. When I click on a line, then the line number is inserted into the self.radek_k_editaci variable in the list_list method. It's alright. However, I can't figure out how to use this value in another python file with a different class. I just can't get the value of this variable in another class in a single python file.

from class_database import *
from gi.repository import Gtk
import gi
import os
gi.require_version("Gtk", "3.0")
from class_database import Database

class Handler:
    def onDestroy(self, *args):
        Gtk.main_quit()

    def __init__(self):
        pass

    def list_seznam(self, listseznam):
        (model, pathlist) = listseznam.get_selected_rows()
        for path in pathlist:
            tree_iter = model.get_iter(path)

            #need value of below variable anywhere else  
            self.radek_k_editaci = model.get_value(tree_iter,0)

handler = Handler()
if __name__ == "__main__":
    
    database = Database()
    builder = Gtk.Builder()
    builder.add_from_file("list.glade")
    seznam = database.vypis_vseho()
    model = builder.get_object("liststore")
    builder.connect_signals(Handler())
    model.clear()
    for i in range(len(seznam)):
        model.append(seznam[i])
    window = builder.get_object("win_list")
    window.show_all()

    Gtk.main()