Add this bonus to the following code: Bonus $50$ points: Add a 'Mode' menu item. The allows the user to switch between standard entry

mode and RPN mode. When in RPN mode the last four items on the stack should be shown in the

display. Add a key for x$<>$y$.$

# $=============================================================================$

# $-----$ MODULE IMPORTS $--------------------------------------------------------$

# $=============================================================================$

import tkinter as tk

from tkinter import messagebox

import math

# $=============================================================================$

# $-----$ MAIN ROUTINE $----------------------------------------------------------$

# $=============================================================================$

class Calculator$($tk$.$Tk$)$:

def $\_\_$init$\_\_($self$)$:

super$().\_\_$init$\_\_()$

self.title$("$Calculator$")$

self.geometry$("400$x$600")$

self.result$\_$var $=$ tk$.$StringVar$()$

self.create$\_$widgets$()$

def create$\_$widgets$($self$)$:

# Display

entry $=$ tk$.$Entry$($self$,$ textvariable$=$self.result$\_$var, font$=(\text{'}$Arial$\text{'},24),$ bd$=10,$ insertwidth$=2,$ width$=14,$ borderwidth$=4)$

entry.grid$($row$=0,$ column$=0,$ columnspan$=4)$

# Buttons

buttons $=[$

$(\text{'}7\text{'},1,0),(\text{'}8\text{'},1,1),(\text{'}9\text{'},1,2),(\text{'}/\text{'},1,3),$

$(\text{'}4\text{'},2,0),(\text{'}5\text{'},2,1),(\text{'}6\text{'},2,2),(\text{'}*\text{'},2,3),$

$(\text{'}1\text{'},3,0),(\text{'}2\text{'},3,1),(\text{'}3\text{'},3,2),(\text{'}-\text{'},3,3),$

$(\text{'}0\text{'},4,0),(\text{'}.\text{'},4,1),(\text{'}=\text{'},4,2),(\text{'}+\text{'},4,3),$

$(\text{'}\text{'},5,0),(\text{'}\text{'},5,1),(\text{'}1/$x$\text{'},5,2),(\text{'}\%\text{'},5,3),$

$(\text{'}$CE$\text{'},6,0)$

$]$

for $($text$,$ row, col$)$ in buttons:

button $=$ tk$.$Button$($self$,$ text$=$text, padx$=20,$ pady$=20,$ font$=(\text{'}$Arial$\text{'},18),$ command$=$lambda t$=$text: self.on$\_$button$\_$click$($t$))$

button.grid$($row$=$row, column$=$col, sticky$=$"nsew"$)$

# Menu

menu $=$ tk$.$Menu$($self$)$

self.config$($menu$=$menu$)$

file$\_$menu $=$ tk$.$Menu$($menu$,$ tearoff$=0)$

file$\_$menu.add$\_$command$($label$=$"Exit", command$=$self.quit$)$

menu.add$\_$cascade$($label$=$"File", menu$=$file$\_$menu$)$

help$\_$menu $=$ tk$.$Menu$($menu$,$ tearoff$=0)$

help$\_$menu.add$\_$command$($label$=$"About", command$=$self.show$\_$about$)$

menu.add$\_$cascade$($label$=$"Help", menu$=$help$\_$menu$)$

def on$\_$button$\_$click$($self$,$ button$)$:

if button $=="="$:

try:

result $=$ eval$($self$.$result$\_$var.get$())$

self.result$\_$var.set$($result$)$

except Exception as e:

self.result$\_$var.set$("$Error$")$

elif button $=="$CE$"$:

self.result$\_$var.set$("")$

elif button $==""$:

try:

value $=$ float$($self$.$result$\_$var.get$())$

self.result$\_$var.set$(-$value$)$

except ValueError:

self.result$\_$var.set$("$Error$")$

elif button $==""$:

try:

value $=$ float$($self$.$result$\_$var.get$())$

self.result$\_$var.set$($math$.$sqrt$($value$))$

except ValueError:

self.result$\_$var.set$("$Error$")$

elif button $=="1/$x$"$:

try:

value $=$ float$($self$.$result$\_$var.get$())$

self.result$\_$var.set$(1/$ value$)$

except $($ValueError$,$ ZeroDivisionError$)$:

self.result$\_$var.set$("$Error$")$

elif button $=="\%"$:

try:

value $=$ float$($self$.$result$\_$var.get$())$

self.result$\_$var.set$($value $/100)$

except ValueError:

self.result$\_$var.set$("$Error$")$

else:

self.result$\_$var.set$($self$.$result$\_$var.get$()+$ button$)$

def show$\_$about$($self$)$:

messagebox.showinfo$("$About$",$ "Author: Cope Hawkins

Date: December $2024")$

if $\_\_$name$\_\_=="\_\_$main$\_\_"$:

app $=$ Calculator$()$

app.mainloop$()$

# $=============================================================================$

# $-----$ FUNCTIONS & DEFINITIONS $-----------------------------------------------$

#