I have made a little Snake game with Python tkinter. It's my first Python program with one Gui. What can i improve?
In my posted code the indentations are partly wrong, because I couldn't format it correctly. I have edited it.

    from tkinter import *
    import random


    boardWidth = 30
    boardHeight = 30
    tilesize = 10

    class Snake():

        def __init__(self):

            self.snakeX = [20, 20, 20]
            self.snakeY = [20, 21, 22]
            self.snakeLength = 3
            self.key = "w"
            self.points = 0

        def move(self): # move and change direction with wasd

            for i in range(self.snakeLength - 1, 0, -1):
                    self.snakeX[i] = self.snakeX[i-1]
                    self.snakeY[i] = self.snakeY[i-1]

            if self.key == "w":
                self.snakeY[0] = self.snakeY[0] - 1

            elif self.key == "s":
                self.snakeY[0] = self.snakeY[0] + 1

            elif self.key == "a":
                self.snakeX[0] = self.snakeX[0] - 1

            elif self.key == "d":
                self.snakeX[0] = self.snakeX[0] + 1

            self.eatApple()

        def eatApple(self):

            if self.snakeX[0] == apple.getAppleX() and self.snakeY[0] == apple.getAppleY():

                self.snakeLength = self.snakeLength + 1

                x = self.snakeX[len(self.snakeX)-1] # Snake grows
                y = self.snakeY[len(self.snakeY) - 1]
                self.snakeX.append(x+1)
                self.snakeY.append(y)

                self.points = self.points + 1
                apple.createNewApple()

        def checkGameOver(self):

            for i in range(1, self.snakeLength, 1):

                if self.snakeY[0] == self.snakeY[i] and self.snakeX[0] == self.snakeX[i]:
                    return True # Snake eat itself

            if self.snakeX[0] < 1 or self.snakeX[0] >= boardWidth-1 or self.snakeY[0] < 1 or self.snakeY[0] >= boardHeight-1:
                return True # Snake out of Bounds

            return False

        def getKey(self, event):

            if event.char == "w" or event.char == "d" or event.char == "s" or event.char == "a" or event.char == " ":
                self.key = event.char

        def getSnakeX(self, index):
            return self.snakeX[index]

        def getSnakeY(self, index):
            return self.snakeY[index]

        def getSnakeLength(self):
            return self.snakeLength

        def getPoints(self):
            return self.points


    class Apple:

        def __init__(self):
            self.appleX = random.randint(1, boardWidth - 2)
            self.appleY = random.randint(1, boardHeight - 2)

        def getAppleX(self):
            return self.appleX

        def getAppleY(self):
            return self.appleY

        def createNewApple(self):
            self.appleX = random.randint(1, boardWidth - 2)
            self.appleY = random.randint(1, boardHeight - 2)

    class GameLoop:

        def repaint(self):

            canvas.after(200, self.repaint)
            canvas.delete(ALL)

            if snake.checkGameOver() == False:

                snake.move()
                snake.checkGameOver()

                canvas.create_rectangle(snake.getSnakeX(0) * tilesize, snake.getSnakeY(0) * tilesize,
                                        snake.getSnakeX(0) * tilesize + tilesize,
                                        snake.getSnakeY(0) * tilesize + tilesize, fill="red")  # Head

                for i in range(1, snake.getSnakeLength(), 1):
                    canvas.create_rectangle(snake.getSnakeX(i) * tilesize, snake.getSnakeY(i) * tilesize,
                                            snake.getSnakeX(i) * tilesize + tilesize,
                                            snake.getSnakeY(i) * tilesize + tilesize, fill="blue")  # Body

                canvas.create_rectangle(apple.getAppleX() * tilesize, apple.getAppleY() * tilesize,
                                        apple.getAppleX() * tilesize + tilesize,
                                        apple.getAppleY() * tilesize + tilesize, fill="green")  # Apple

            else:   # GameOver Message
                canvas.delete(ALL)
                canvas.create_text(150, 100, fill="darkblue", font="Times 20 italic bold", text="GameOver!")
                canvas.create_text(150, 150, fill="darkblue", font="Times 20 italic bold",
                                       text="Points:" + str(snake.getPoints()))


    snake = Snake()
    apple = Apple()
    root = Tk()

    canvas = Canvas(root, width=300, height=300)
    canvas.configure(background="yellow")
    canvas.pack()

    gameLoop = GameLoop()
    gameLoop.repaint()

    root.title("Snake")
    root.bind('<KeyPress>', snake.getKey)
    root.mainloop()

Any help would be really appreciated.