Why is the score on the ingame screen not updating?

Question

Here is the code.

import random
import arcade


SCREEN_WIDTH = 960
SCREEN_HEIGHT = 720
SCREEN_TITLE = "Гонки"
CAR_ANGLE = 20
CAR_SPEED = 5
WALL_SPEED = 5


class Car(arcade.Sprite):
    def update(self):
        self.center_x += self.change_x


class Wall(arcade.Sprite):
    def __init__(self, filename, scale):
        super().__init__(filename, scale)
        self.score = 0  # Initialize the score attribute

    def update(self):
        self.center_y -= self.change_y
        if self.top < 0:
            self.bottom = SCREEN_HEIGHT + random.randint(0, SCREEN_HEIGHT)
            self.center_x = random.randint(168, SCREEN_WIDTH - 168)
            self.score += 1  # Increment the score
        return self.score  # Return the updated score


class MyGame(arcade.Window):
    def __init__(self, width, height, title):
        super().__init__(width, height, title)
        self.bg = arcade.load_texture('bg.png')
        self.car = Car("yellow_car.png", 0.8)
        self.car.center_x = SCREEN_WIDTH / 2
        self.car.center_y = 100
        self.score = 0  # Initialize score attribute for the game
        self.wall = Wall('wall.png', 0.8)
        self.wall.center_y = SCREEN_HEIGHT
        self.wall.center_x = random.randint(168, SCREEN_WIDTH - 168)
        self.wall.change_y = WALL_SPEED
        self.game = True

    def update(self, delta_time: float):
        if self.game:
            self.car.update()
            self.score = self.wall.update()  # Update score from Wall class

    def on_draw(self):
        self.clear()
        arcade.draw_texture_rectangle(SCREEN_WIDTH / 2, SCREEN_HEIGHT / 2, SCREEN_WIDTH, SCREEN_HEIGHT, self.bg)
        self.car.draw()
        self.wall.draw()
        if self.game:
            arcade.draw_text(f"Your score is {self.score}", 10, 10, arcade.color.AFRICAN_VIOLET, font_size=26)
        else:
            arcade.draw_text("Авария!", SCREEN_WIDTH / 2 - 150, SCREEN_HEIGHT / 2, arcade.color.CYAN, font_size=60)

        if self.score == 10:
            arcade.draw_text("Выигрыш!", SCREEN_WIDTH / 2 - 150, SCREEN_HEIGHT / 2, arcade.color.GOLD, font_size=60)

    def update(self, delta_time: float):
        if self.game:
            self.car.update()
            self.wall.update()
            if arcade.check_for_collision(self.car, self.wall):
                self.game = False

    def on_key_press(self, symbol: int, modifiers: int):
        if self.game:
            if symbol == arcade.key.LEFT:
                self.car.change_x = -CAR_SPEED
                self.car.angle = CAR_ANGLE
            if symbol == arcade.key.RIGHT:
                self.car.change_x = CAR_SPEED
                self.car.angle = -CAR_ANGLE

    def on_key_release(self, symbol: int, modifiers: int):
        if symbol == arcade.key.LEFT:
            self.car.change_x = 0
            self.car.angle = 0
        if symbol == arcade.key.RIGHT:
            self.car.change_x = 0
            self.car.angle = 0


window = MyGame(SCREEN_WIDTH, SCREEN_HEIGHT, SCREEN_TITLE)
arcade.run()

There is a problem especially in this chunk:

    def on_draw(self):
        self.clear()
        arcade.draw_texture_rectangle(SCREEN_WIDTH / 2, SCREEN_HEIGHT / 2, SCREEN_WIDTH, SCREEN_HEIGHT, self.bg)
        self.car.draw()
        self.wall.draw()
        if self.game:
            arcade.draw_text(f"Your score is {self.score}", 10, 10, arcade.color.AFRICAN_VIOLET, font_size=26)

When I start the game, on the screen it should say how much the score is when the plank goes below the 0y coordinate. But when it goes by, nothing happens and the score stays at zero.