I have the following code for a python tkinter GUI event handling calendar, Unfortunately my functions are not working togethor properly, I am getting variable undefined errors and others, can you please help to fix this code so that it actually ADDS, SAVES, VIEWS, EDITS, and DELETES events when the buttons are pressed.

#MAIN WINDOW ITEMS

# Create a dictionary to store events

events $=\{\}$

# Create a listbox to display events

listbox$\_$events $=$ tk$.$Listbox$($root$,$ width$=50,$ height$=5)$

listbox$\_$events.pack$()$

# Define a function to check for existing events

# Get the list of events from the listbox

# Check if the event title already exists in the list

def check$\_$for$\_$existing$\_$events$($listbox$\_$events, event$\_$title, cal$)$:

date$\_$selected $=$ cal.get$\_$date$()$

# Get the list of events from the listbox

events $=$ listbox$\_$events.get$(0,$ tk$.$END$)$

# Check if the event title already exists in the list

for event in events:

if event.startswith$($event$\_$title$)$:

return True

return False

# Factory function to manage the state of the variables

def event$\_$manager$()$:

# Encapsulated variables

listbox$\_$events $=$ None

event$\_$title $=$ None

event$\_$time $=$ None

event$\_$descript $=$ None

date$\_$selected $=$ None

def set$\_$variables$($lb$\_$events, e$\_$title, e$\_$time, e$\_$descript, date$\_$sel$)$:

nonlocal listbox$\_$events, event$\_$title, event$\_$time, event$\_$descript, date$\_$selected

listbox$\_$events $=$ lb$\_$events

event$\_$title $=$ e$\_$title

event$\_$time $=$ e$\_$time

event$\_$descript $=$ e$\_$descript

date$\_$selected $=$ date$\_$sel

def get$\_$variables$()$:

return listbox$\_$events, event$\_$title, event$\_$time, event$\_$descript, date$\_$selected

# Define a function to ADD an event

def add$\_$event$($cal$)$:

nonlocal date$\_$selected, event$\_$title, event$\_$time, event$\_$descript

date$\_$selected $=$ cal.get$\_$date$()$

event$\_$title $=$ entry$\_$event$\_$title.get$()$

event$\_$time $=$ entry$\_$event$\_$time.get$()$

event$\_$descript $=$ entry$\_$event$\_$descript.get$()$

if not event$\_$title or not event$\_$time:

messagebox.showwarning$("$Warning$",$ "Please enter an event title and event time."$)$

return

elif check$\_$for$\_$existing$\_$events$($listbox$\_$events, event$\_$title, cal$)$:

messagebox.showinfo$("$Event exists", "Event exists, please select another action."$)$

return

else:

response $=$ messagebox.askyesno$("$Add Event", $"$Do you want to add an event?"$)$

if response:

open$\_$event$\_$management$\_$window$()$

return set$\_$variables, get$\_$variables, add$\_$event

# Define a function to SAVE an event

def save$\_$event$($cal$)$:

nonlocal date$\_$selected, event$\_$title, event$\_$time, event$\_$descript

date$\_$selected $=$ cal.get$\_$date$()$

event$\_$title $=$ entry$\_$event$\_$title.get$()$

event$\_$time $=$ entry$\_$event$\_$time.get$()$

event$\_$descript $=$ entry$\_$event$\_$descript.get$()$

if event$\_$title and event$\_$time:

event$\_$date $=$ cal.selection$\_$get$()$

events$[$event$\_$title$]=\{"$Time$"$: event$\_$time, "Date": event$\_$date, "Description": event$\_$descript$\}$

listbox$\_$events.insert$($tk$.$END, event$\_$title$)$

highlight$\_$event$($event$\_$title, listbox$\_$events$)$

else:

messagebox.showwarning$("$Warning$",$ "Event title and time cannot be empty."$)$

# Define a function to HIGHLIGHT an event

def highlight$\_$event$($event$\_$title, listbox$\_$events$)$:

listbox$\_$events.itemconfig$($listbox$\_$events.size$()-1,\{\text{'}$bg$\text{'}$:'cyan'$\})$

# Define a function to SAVE events to a file

def save$\_$events$\_$to$\_$file$($filename$,$ listbox$\_$events$)$:

with open$($filename$,"$w$")$ as file:

for event in listbox$\_$events.get$(0,$ tk$.$END$)$:

file.write$($event $+"$

$")$

# Define a function to VIEW events

def view$\_$event$($listbox$\_$events, events$)$:

selected$\_$event $=$ event$\_$listbox.get$($tk$.$ANCHOR$)$

if selected$\_$event:

event$\_$info $=$ events$[$selected$\_$event$]$

messagebox.showinfo$("$Event Details", f$"$Title: $\{$selected$\_$event$\}$

Time: $\{$event$\_$info$["$Time$"]\}$

Date: $\{$event$\_$info$["$Date$"]\}$

Description: $\{$event$\_$info$["$Description$"]\}")$

# Create a function to EDIT an event

def edit$\_$event$($listbox$\_$events, cal, event$\_$time, event$\_$title$)$:

date$\_$selected $=$ cal.get$\_$date$()$

selected$\_$event $=$ event$\_$listbox.get$($tk$.$ANCHOR$)$

if selected$\_$event:

event$\_$time$\_$old $=$ selected$\_$event.split$("-")[0]$

# Find the event and update its time and title

for event in events.get$($date$\_$selected, $[])$:

if event$["$event time"$]==$ event$\_$time$\_$old:

event$["$event time"$]=$ event$\_$time

event$["$event title"$]=$ event$\_$title

messagebox.showinfo$("$Event Updated", f$"$Event updated for $\{$date$\_$selected$\}$: $\{$event$\_$title$\}$ at $\{$event$\_$time$\}")$

return

messagebox.showinfo$("$Event Not Found", f$"$No event found for $\{$date$\_$selected$\}")$

else:

messagebox.showwarning$("$Warning$",$ "Please select an event to edit."$)$

# Create a function to DELETE an event

# Find and delete the event from the events dictionary

# Update the listbox

def deletuntitled $*-$ Sublime Text $($UNREGISTERED$)$

untitled

#MAIN WINDOW ITEMS # Create a dic