input: Write a function to remove duplicates from a list and return the list with unique elements in the same order they appear.
  
  def remove_duplicates(my_list):
   return list(dict.fromkeys(my_list))
  
  my_list = [1, 2, 3, 4, 3, 2, 1]
  
  assert remove_duplicates(my_list) == [1, 2, 3, 4]
  assert remove_duplicates([1, 1, 2, 2, 3, 3, 4, 4]) == [1, 2, 3, 4]
  assert remove_duplicates([5, 6, 7, 8, 9, 9, 8, 7, 6, 5]) == [5, 6, 7, 8, 9]
  assert remove_duplicates([]) == []
  assert remove_duplicates([1, 2, 3, 4, 5]) == [1, 2, 3, 4, 5]
output: def remove_duplicates(my_list):
      seen = set()
      result = []
      for item in my_list:
          if item not in seen:
              seen.add(item)
              result.append(item)
      return result