问Python，Tkinter -关于代码的一些一般性问题

EN

import tkinter as tk    
from tkinter import *
from tkinter import ttk

from CreateProgramMain import main
import GlobalVariables

class Test():
    ####################################################################################
    def __init__(self):
        self.Progress=0
        self.root = tk.Tk()
        self.root.title(GlobalVariables.strAppName)
        self.root.geometry('400x200')
    
        lbl = Label(self.root, text="Please choose environment.",font=("Arial Bold", 12))
        lbl.grid(column=2, row=0,sticky='e') 

        def btnTestClicked():
            main("TEST",self)
        btnTest=tk.Button(self.root, text="Test Environment", command=btnTestClicked)
        btnTest.grid(column=2, row=15)

        #Place progress bar
        pb = ttk.Progressbar(self.root,orient='horizontal',mode='determinate',length=200)
        pb.grid(column=1, row=65, columnspan=2, padx=10, pady=20)    
        pb["value"]=self.Progress
        pb["maximum"]=100

        btnProg = tk.Button(self.root, text = 'update', command=self.fnUpdateProgress)
        btnProg.grid(column=2, row=75)
        self.root.mainloop()

    def fnUpdateProgress(self): #why i cant insert variable inside?
            pb["value"]=self.Progress
            self.Progress=self.Progress+5
            pb.update()
app = Test()