updating tkinter window for text background changes - python-3.x

Question

Trying to show a green or red background in the text field of the answer to the simple addition quizzer.
Currently in PyCHarm complains that:
Entry.grid_configure(background = "red")
TypeError: grid_configure() missing 1 required positional argument: 'self'
0
I can't seem to figure this out. Any help is appreciated.
Here's the code so far:
from tkinter import *
import random
class MainGUI:
def __init__(self):
window = Tk() # Create the window
window.title("Addition Quizzer") # Set the title
#window.width(len(window.title()))
self.number1 = random.randint(0, 9)
self.number2 = random.randint(0, 9)
Label(window, text = "+").grid(row = 2, column = 1, sticky = E)
Label(window, text = "Answer").grid(row = 3, column = 1, sticky = W)
self.firstNumber = StringVar()
Label(window, text = self.number1, justify = RIGHT).grid(row = 1, column = 2)
self.secondNumber = StringVar()
Label(window, text = self.number2, justify = RIGHT).grid(row = 2, column = 2)
self.entry = StringVar()
Entry(window, textvariable = self.entry, justify = CENTER, width = 4, background = "grey").grid(row = 3, column = 2)
Button(window, text = "Answer:", command = self.computeAnswer).grid(row = 4, column = 1, sticky = E)
self.result = StringVar()
Label(window, textvariable = self.result).grid(row = 4, column = 2)
window.mainloop() # Create the event loop
def computeAnswer(self):
self.result.set(format(self.number1 + self.number2))
if self.entry == self.result:
self.displayCorrect()
else:
self.displayIncorrect()
def displayCorrect(self):
# self.correctAnswer = "Correct"
# Label(self.window, text = self.correctAnswer, background = "green", justify = RIGHT).grid(row = 5, column = 2)
Entry.grid_configure(background = "green")
def displayIncorrect(self):
# self.incorrectAnswer = "Incorrect"
# Label(self.window, text = self.incorrectAnswer, background = "red", justify = RIGHT).grid(row = 5, column = 2)
Entry.grid_configure(background = "red")
MainGUI()

Answer 1

If you had read and followed this in the Help Center material, you would have reduced your code to the following, which still gets the same error message.
from tkinter import *
Entry.grid_configure()
The message refers to the fact that Python instance methods require an instance. This is usually done by calling the method on an instance instead of the class. Otherwise, an instance must be given as the first argument. Consider
mylist = []
mylist.append(1)
list.append(mylist, 2)
print(mylist)
# [1, 2]
You need to save a reference to your Entry box. Change
Entry(window, ..., background = "grey").grid(...)
to
self.entry = Entry(window, ..., background = "grey").grid(...)
I do not know if calling .grid_configure(background=color will do what you want.
This will, I am sure.
self.entry['background'] = 'red'