title: pygame code thinks im putting in a string but it should be a surface
body: <p>Im doing some computer science course work and am trying to find a frame for making a gif this is what I
  have at the moment but I cannot figure out whats wrong. Im pretty new to coding (only been coding for about a month) so any bonus advice would be appreciated.</p>
  <pre><code>import pygame
  import sys
  
  pygame.init()
  
  
  class Animation(pygame.sprite.Sprite):
  
      def __init__(self, images, time_interval):
          super(Animation, self).__init__()
          self.images = images
          self.image = self.images[0]
          self.time_interval = time_interval
          self.index = 0
          self.timer = 0
  
      def update(self, seconds):
          self.timer += seconds
          if self.timer &gt;= self.time_interval:
              self.image = self.images[self.index]
              self.index = (self.index + 1) % len(self.images)
              self.timer = 0
  
  
  def create_images():
      images = []
      for i in xrange(6):
          image = pygame.Surface((256, 256))
          image.fill((255 - i * 50, 255, i * 50))
          images.append(image)
      return images
  
  
  def main():
      images = ('assets\\image\\earth_troll\\idle_1.png',
                'assets\\image\\earth_troll\\idle_3.png',
                'assets\\image\\earth_troll\\idle_5.png',
                'assets\\image\\earth_troll\\idle_7.png',
                'assets\\image\\earth_troll\\idle_9.png')  # Or use a list of your own images.
      a = Animation(images, 0.25)
  
      # Main loop.
      while True:
          seconds = clock.tick(FPS) / 1000.0  # 'seconds' is the amount of seconds each loop takes.
  
          for event in pygame.event.get():
              if event.type == pygame.QUIT:
                  sys.exit()
  
          a.update(seconds)
          screen.fill((0, 0, 0))
          screen.blit(a.image, (250, 100))
          pygame.display.update()
  
  
  if __name__ == '__main__':
      screen = pygame.display.set_mode((720, 480))
      clock = pygame.time.Clock()
      FPS = 60
      main()
  </code></pre>
  <p>I'm getting the error</p>
  <pre><code>TypeError: argument 1 must be pygame.Surface, not str
  </code></pre>
  <p>but I cannot figure out why.</p>