multiple checkboxes again in python

I am a noob, I am trying to create many checkboxes at once. ultimately, my program would create folders in the same directory, depending on which ones have been checked. I simply do not get the IntVar() use. I would love for some of the boxes to be ticked by default...according to the entries in my dictionary I even tried to put the "variable" = 1 in my loop and the boxes are not ticked!!!

import os
from tkinter import *


def create_folders():
    for item in list_of_folders:
        print(item)
            # os.mkdir(list_of_folders[item])


list_of_folders = {"Audio":0,"AVI":0, "Footage":1, "GFX":1, "MP4":1, "MOV":1, "MPG":0,  "Photography":1, "Press":1}
num_row=0
window = Tk()
var=[]
window.title("Folder Creation v1.0")
window.minsize(300, 200)
window.config(padx=100, pady=100)

for item in list_of_folders:
    num_row +=1
    Checkbutton(window, text=item, variable=list_of_folders[item]).grid(row=num_row, sticky=W)



Label(window, text="").grid(column=0, row=10, sticky=W)

Button(window, text="Create Folders", command=create_folders).grid(column=0, row=15, sticky=W)

Button(window, text="Exit", command=window.destroy).grid(column=1, row=15, sticky=W)

window.mainloop()