So, I am making the Snake() module in my code, having it move, and my left() function isn’t working! It doesn’t do anything. I need help.

So, I was setting its heading, and I made it to 180, and it was doing nothing. I do not know what is wrong with it. Please help! Here is my code.

import turtle as t


STARTING_POSITIONS = [(0, 0), (-20, 0), (-40, 0)]
MOVE_DISTANCE = 20


class Snake:
    def __init__(self):

        self.segments = []

        for position in STARTING_POSITIONS:
            new_turtle = t.Turtle(shape='square')
            new_turtle.penup()
            new_turtle.color("white")
            new_turtle.goto(position)
            self.segments.append(new_turtle)

    def move(self):
        for seg_num in range(len(self.segments) - 1, 0, -1):
            new_x = self.segments[seg_num - 1].xcor()
            new_y = self.segments[seg_num - 1].ycor()
            new_coords = (new_x, new_y)
            self.segments[seg_num].goto(new_coords)
        self.segments[0].forward(MOVE_DISTANCE)

    def up(self):
        self.segments[0].setheading(90)

    def left(self):
        self.segments[0].setheading(180)

    def down(self):
        self.segments[0].setheading(270)

    def right(self):
        self.segments[0].setheading(0)

It’s in two files. Here is the other:

import turtle as t
from snake import Snake
import time

screen = t.Screen()
screen.bgcolor('black')
screen.setup(width=600, height=600)
screen.title("Snake(Still in Progress)")
screen.tracer(0)
snake = Snake()
screen.update()

screen.listen()


game_is_on = True

while game_is_on:
    screen.update()
    time.sleep(0.1)
    screen.onkey(snake.up, "Up")
    screen.onkey(snake.down, "Down")
    screen.onkey(snake.up, "Left")
    screen.onkey(snake.right, "Right")
    snake.move()


screen.exitonclick()