input: Write a function to delete all duplicates in a given list of numbers. Return a list that contains only unique elements in the same order they appear in the input list. If the input list is empty, return an empty list.
  def deleteDuplicates(list): 
      final_list = [] 
      for num in list: 
          if num not in final_list: 
              final_list.append(num) 
      return final_list
  
  assert deleteDuplicates([1, 2, 3, 2, 1])==[1, 2, 3]
  assert deleteDuplicates([5, 5, 5, 5])==[5]
  assert deleteDuplicates([1, 2, 3, 4, 5])==[1, 2, 3, 4, 5]
  assert deleteDuplicates([])==[]
  assert deleteDuplicates([7, 3, 7, 3, 7, 3])==[7, 3]
output: def deleteDuplicates(list): 
      final_list = [] 
      for num in list: 
          if num not in final_list: 
              final_list.append(num) 
      return final_list