title: 'tuple' object is not callable (python)
body: <p>so this is my first game im working on (snake) and it gave me an error: <code>ln 21, in update
  self.rect.centerx += self.direction(0) *2, 'tuple' object is not callable.</code>
  and i've looked it up for answers but i didnt seem to find my problem and i dont know what 'tuple' means, the full game-code is here:</p>
  
  <pre><code>import pygame
  from pygame.locals import *
  
  
  class SnakeHead(object):
      def __init__(self):
          self.image = pygame.image.load('data/snake_head.png') 
          self.rect = self.image.get_rect()
          self.rect.centerx = 320
          self.rect.centery = 240    
  
          self.direction = (0,-1) 
          self.crashed = False
  
  
      def render(self, screen):
          screen.blit(self.image, self.rect)
  
      def update(self):
          self.rect.centerx += self.direction(0) * 2
          self.rect.centery += self.direction(1) * 2
  
          if self.rect.left &lt; 0:
              self.rect.left = 0
              self.crashed = True
  
          if self.rect.right &gt; 639:
                  self.rect.right = 639
                  self.crashed = True
  
          if self.rect.top &lt; 0:
                  self.rect.top = 0
                  self.crashed = True
  
          if self.rect.bottom &gt; 479:
                  self.rect.bottom = 479
                  self.crashed = True 
  
  def run_game():
      pygame.init()
  
  screen = pygame.display.set_mode((640,480)) 
  
  snakehead = SnakeHead()
  
  clock = pygame.time.Clock() 
  
  
  
  
  while 1:
  
      clock.tick(32)
  
      for event in pygame.event.get():
          if event.type == QUIT:
              pygame.quit()
              return 
  
  
      screen.fill((175,175,175))
  
      snakehead.update() 
      snakehead.render(screen) 
  
      pygame.display.flip() `
  </code></pre>
  
  <p>i've been asking myself what the probelem was for over 2 hours, but couldnt find anything and would be super happy if someone could tell me :)</p>
  
  <p>-Xattics</p>