I Fail To Insert The Values To Tkinter Listbox

I have written this piece of code to implement data to Listbox when I open a file, though there is an AttributeError, I have failed to understand to fix this error.

from Tkinter import *
import tkFileDialog
import csv
from imdb import IMDb


class STproject:

    def __init__(self,app): #1

        self.mlb=LabelFrame(app, text='Movie Recommendation Engine')
        self.mlb.grid()
        self.lframe3=LabelFrame(self.mlb,text="Movies/Users",background='purple')
        self.lframe3.grid(row=0,column=1)
        self.framebutton=Frame(self.mlb,background='pink',height=50,width=50)
        self.framebutton.grid(row=0,column=0)

        self.buttonsnlabels()

    def buttonsnlabels(self):

        self.ratingbutton=Button(self.framebutton,text='Upload Rating',command=lambda :self.file2())
        self.ratingbutton.grid()
        self.lb1 = Listbox(self.lframe3)
        self.lb1.grid()
        self.lb1.insert(self.emp2) //self.emp2 its locally ?

    def file2(self):
        umovies=tkFileDialog.askopenfilename()
        f=open(umovies)
        self.emp2=[]
        self.csv_file2 = csv.reader(f)
        for line2 in self.csv_file2:
            self.emp2.append(line2[2])

root=Tk()
root.title()
application=STproject(root)
root.mainloop()

and here you have the full error:

Traceback (most recent call last):
  File "C:/Users/Umer Selmani/Desktop/voluntarily/Voluntiraly.py", line 846, in <module>
    application=STproject(root)
  File "C:/Users/Umer Selmani/Desktop/voluntarily/Voluntiraly.py", line 814, in __init__
    self.a=self.emp2[1]
AttributeError: STproject instance has no attribute 'emp2'

You have this error because your .insert(self.emp2) is executed after button is created, not after user clicked button. And at this moment you don't have self.emp2 yet - you create it later in file2().

You have to use .insert(self.emp2) in file2()

EDIT: You have to use insert inside for loop and add every item separatelly

            self.lb1.insert('end', line2[2])

so you could skip self.emp2 if you don't need it later

Or you have to use * to put items from list in separated lines

self.lb1.insert('end', *self.emp2)

Code

def buttonsnlabels(self):

        self.ratingbutton = Button(self.framebutton, text='Upload Rating', command=self.file2)
        self.ratingbutton.grid()

        self.lb1 = Listbox(self.lframe3)
        self.lb1.grid()


def file2(self):
        #self.emp2 = []

        umovies = tkFileDialog.askopenfilename()

        f = open(umovies)
        self.csv_file2 = csv.reader(f)

        for line2 in self.csv_file2:
            #self.emp2.append(line2[2])
            self.lb1.insert('end', line2[2])

        #self.lb1.insert('end', *self.emp2)