Help with pygame tutorial

[djwilson0495]

I'm trying to make a pygame window where I can enter and edit text. I'm following a tutorial as a base for my code but I'm getting an the following error:

Error:
 File "c:\Users\djwil\Documents\python\python crash course\Projects\Alien invasion\print.py", line 39, in Print  
    text += event.unicode
AttributeError: 'Event' object has no attribute 'unicode'

this is my code:

import pygame
from pygame.locals import *
import time

class Print:
    """Draw text to the screen."""
    # text is editable with the keyboard
    
    # options for font and background colour
    BLACK = (0, 0, 0)
    RED = (255, 0, 0)
    GREEN = (0, 255, 0)
    BLUE = (0, 0, 255)
    GRAY = (200, 200, 200)

    pygame.init()
    screen = pygame.display.set_mode((640, 240)) 
    # creates a screen 640 x 240 pixels in size

    sysfont = pygame.font.get_default_font()
    print('system font :', sysfont)
    text = 'This text is editable'
    font = pygame.font.SysFont(None, 24)
    img = font.render(text, True, RED)
    rect = img.get_rect()
    

    running = True
    background = GRAY
    while running:
        for event in pygame.event.get():
            if event.type == QUIT:
                running = False
        if event.type == KEYDOWN:
            if event.key == K_BACKSPACE:
                if len(text)>0: # if length of text is > 0
                    text = text[:-1] # delete the last letter in the string
        else:
            text += event.unicode
            # else add the letter to the end of the string
        img = font.render(text, True, RED)
        rect.size=img.get_size()
        cursor.topleft = rect.topright

        screen.fill(background)
        screen.blit(img, (20, 20))
        pygame.display.update()

    pygame.quit()