title: Python missing argument
body: <p>Where is my fault</p>
  
  <p>"this code is only part of my code
  I just copied part of it"</p>
  
  <pre><code>import turtle
  
  wn=turtle.Screen()
  wn.bgcolor("black")
  wn.title("Pacman")
  wn.setup(900,700)
  class Pacman(turtle.Turtle):
      def __init__(self):
          turtle.Turtle.__init__(self)
          self.shape("square")
          self.color("yellow")
          self.penup()
          self.speed(0)
      def up(self):
          self.goto(self.xcor(),self.ycor()+24)
      def down(self):
          self.goto(self.xcor(),self.ycor()-24)
      def left(self):
          self.goto(self.xcor()-24,self.ycor())
      def right(self):
          self.goto(self.xcor()+24,self.ycor())
  
  wn.listen()
  wn.onkey(Pacman.down, "Down")
  wn.onkey(Pacman.up, "Up")
  wn.onkey(Pacman.right, "Right")
  wn.onkey(Pacman.left, "Left")
  wn.tracer(0)
  
  while True:
     wn.update()
  </code></pre>
  
  <p>Fail </p>
  
  <pre><code>Exception in Tkinter callback
  Traceback (most recent call last):
  File "C:\Users\asus\AppData\Local\Programs\Python\Python37- 
  32\lib\tkinter\__init__.py", line 1702, in __call__
  
  return self.func(*args)
  
  File "C:\Users\asus\AppData\Local\Programs\Python\Python37- 
  32\lib\turtle.py", line 686, in eventfun
  
  fun()
  TypeError: up() missing 1 required positional argument: 'self'
  </code></pre>
  
  <p>When I click Right,Down,Up or Left Button square not moving and in console writing this fail  </p>