input: 
  def deleteDuplicates(list):
      """Deletes all duplicates in a given list of numbers.
      >>> deleteDuplicates([1, 2, 3, 4, 4, 3, 2, 1])
      [1, 2, 3, 4]
      >>> deleteDuplicates([5, 5, 5, 5, 5])
      [5]
      """
      final_list = []
      for num in list:
          if num not in final_list:
              final_list.append(num)
      return final_list
  
output:     final_list = []
      for num in list:
          if num not in final_list:
              final_list.append(num)
      return final_list