non-blocking gui while code in while loop

i found workable solution

#from Tkinter import *
from Tkinter import Tk, Text, Frame, Scrollbar, END
import time



# while True:
#     ROOT.update()
# 
#     time.sleep(10)
#     txt.insert(END, "hello here\n")
#     txt.pack()    


import threading
class ThreadingExample(object):
    """ Threading example class
    The run() method will be started and it will run in the background
    until the application exits.
    """

    def __init__(self, interval=1):
        """ Constructor
        :type interval: int
        :param interval: Check interval, in seconds
        """
        self.interval = interval

        thread = threading.Thread(target=self.run, args=())
        thread.daemon = True                            # Daemonize thread
        thread.start()                                  # Start the execution

    def run(self):
        """ Method that runs forever """
        time.sleep(1)
        global ROOT
        while True:
            ROOT.update()

            time.sleep(2)
            txt.insert(END, "hello here\n")
            txt.pack()   

            print "aa" 




global ROOT
ROOT = Tk()
# create a Frame for the Text and Scrollbar
txt_frm = Frame(ROOT, width=600, height=600)
txt_frm.pack(fill="both", expand=True)
# ensure a consistent GUI size
txt_frm.grid_propagate(False)
# implement stretchability
txt_frm.grid_rowconfigure(0, weight=1)
txt_frm.grid_columnconfigure(0, weight=1)
# create a Text widget
txt = Text(txt_frm, borderwidth=3, relief="sunken")
txt.config(font=("consolas", 12), undo=True, wrap='word')
txt.grid(row=0, column=0, sticky="nsew", padx=2, pady=2)
# create a Scrollbar and associate it with txt
scrollb = Scrollbar(txt_frm, command=txt.yview)
scrollb.grid(row=0, column=1, sticky='nsew')
txt['yscrollcommand'] = scrollb.set
txt.insert(END, "hello\n")
txt.pack()

example = ThreadingExample()