python GUI to do list

from tkinter import *

window = Tk()
window.title("ToDo List by Justin Hagerty")
window.geometry('400x310')
#to add the spacers on each side of the UI
window.columnconfigure(2, weight=1)

class LPB():
    LPButtons = []
class RPI():
    RPInput = []

def addListItem():

def removeListItem():
    print("removeListItem")
def refreshList():
    print("refreshList")

def windowPerm():
    leftPanelButton()
    rightPanelInput()
    window.mainloop()

def leftPanelButton():
    LPB.LPButtons.append(Button(window, text="add", command=addListItem))
    LPB.LPButtons.append(Button(window, text="remove", command=removeListItem))
    LPB.LPButtons.append(Button(window, text="refresh", command=refreshList))
    i = 0
    for p in LPB.LPButtons:
        p.grid(row=int(i), column=0, columnspan=2, padx=10, pady=10)
        p.config(width=10)
        i = i + 1

def rightPanelInput():
    RPI.RPInput.append(Entry(window, width=46))
    RPI.RPInput.append(Text(window, width=35, height=10))
    #RPI.RPInput.append(Entry(window))
    i = 0
    for p in RPI.RPInput:
        p.grid(row=int(i), column=2, columnspan=3, padx=10)
        i = i + 1
    RPI.RPInput[1].grid(rowspan=4)

windowPerm()