old_contents: """
  Merge function for 2048 game.
  """
  
  def merge(line):
      """
      Function that merges a single row or column in 2048.
      """
      l = len(line)
      s1 = [0]*l
      j = 0
      for i in range(l):
      	if l[i] != 0:
      		s1[j] = l[i]
  
      return []
  
  a = [2,0,2,4]
  
  print merge(a)
new_contents: """
  Merge function for 2048 game.
  """
  
  def merge(line):
      """
      Function that merges a single row or column in 2048.
      """
      l = len(line)
      s1 = [0]*l
      j = 0
      for i in range(l):
          if line[i] != 0:
              s1[j] = line[i]
              j += 1
      return s1
  
  a = [2,0,2,4]
  
  print (merge(a))
subject: Modify the correct merge 1 fct