How to stop random ranges spawning in certain areas that vary?

I am making snake using pygame for a school challenge and it is functional and working but the problem I have is that sometimes when the snake eats the food the new food spawns inside the snake's tail. The reason I'm not sure of how to change this is because the way it generates the random placement of the food is using randomrange on a grid, and I do not know of anyway to exclude the snakes tail from this range/ regenerate it if it does spawn within there. Is this a fundemental problem with using random.randrange or is there a simple fix while retaining most of the code. Highlighted code top two lines below

foodX = round(random.randrange(0,display_width-snake_block)/snake_block)*snake_block
foodY = round(random.randrange(0,display_height-snake_block)/snake_block)*snake_block

import pygame
import time
import random

pygame.init()

display_width = 600
display_height = 600
display = pygame.display.set_mode((display_width,display_height))
pygame.display.set_caption("Snake")

pureblue = (0,0,255)
purered = (255,0,0)
puregreen = (0,255,0)
red = (125,25,25)
green = (25,125,25)
white = (255,255,255)
black = (1,1,1)
grey = (20,20,20)
darkgrey = (15,15,15)


clock = pygame.time.Clock()

snake_block = 30
snake_speed = 10

font_style = pygame.font.SysFont(None, 50)

def user_snake(snake_block, snake_List):
    for x in snake_List:
        pygame.draw.rect(display,green,[x[0],x[1], snake_block, snake_block])

def drawGrid(surf):
    blockSize = snake_block
    surf.fill(grey)
    for x in range(display_width):
        for y in range(display_height):
            rect = pygame.Rect(x*blockSize, y*blockSize,blockSize, blockSize)
            pygame.draw.rect(surf,darkgrey, rect, 1)
grid_surf = pygame.Surface(display.get_size())
drawGrid(grid_surf)

def message(msg, colour):
    text = font_style.render(msg, True, colour)
    display.blit(text, [0, display_height/4])

def SnakeGameLoop():
    game_over = False
    game_close = False
    X = display_width/2
    Y = display_height/2

    X_change = 0
    Y_change = 0
    
    snake_List = []
    Length_of_snake = 1

    foodX = round(random.randrange(0,display_width-snake_block)/snake_block)*snake_block
    foodY = round(random.randrange(0,display_height-snake_block)/snake_block)*snake_block

    while not game_over:
        while game_close == True:
            message("You Lost! Press Q-Quit or C-Play Again", purered)
            pygame.display.update()
 
            for event in pygame.event.get():
                if event.type == pygame.KEYDOWN:
                    if event.key == pygame.K_q:
                        game_over = True
                        game_close = False
                    if event.key == pygame.K_c:
                        SnakeGameLoop()
        for event in pygame.event.get():
            if event.type == pygame.QUIT:
                game_over = True
            if event.type == pygame.KEYDOWN:
                if event.key == pygame.K_LEFT:
                    X_change = -snake_block
                    Y_change = 0
                elif event.key == pygame.K_RIGHT:
                    X_change = snake_block
                    Y_change = 0
                elif event.key == pygame.K_UP:
                    X_change = 0
                    Y_change = -snake_block
                elif event.key == pygame.K_DOWN:
                    X_change = 0
                    Y_change = snake_block

                if event.key == pygame.K_a:
                    X_change = -snake_block
                    Y_change = 0
                elif event.key == pygame.K_d:
                    X_change = snake_block
                    Y_change = 0
                elif event.key == pygame.K_w:
                    X_change = 0
                    Y_change = -snake_block
                elif event.key == pygame.K_s:
                    X_change = 0
                    Y_change = snake_block

        if X >= display_width or X < 0 or Y >= display_height or Y < 0:
            game_close = True

        X += X_change
        Y += Y_change
        display.blit(grid_surf, (0,0))
        pygame.draw.rect(display, red, [foodX, foodY, snake_block, snake_block])
        snake_Head = []
        snake_Head.append(X)
        snake_Head.append(Y)
        snake_List.append(snake_Head)

        if len(snake_List) > Length_of_snake:
            del snake_List[0]

        for x in snake_List[:-1]:
            if x == snake_Head:
                game_close = True

        user_snake(snake_block,snake_List)

        pygame.display.update()

        if X == foodX and Y == foodY:
            foodX = round(random.randrange(0, display_width - snake_block) / snake_block) * snake_block
            foodY = round(random.randrange(0, display_height - snake_block) / snake_block) * snake_block
            Length_of_snake += 1

        clock.tick(snake_speed)


    pygame.quit()
    quit()
SnakeGameLoop()