input: Write a function that removes duplicates from a given list and returns the list with unique elements in their original order. If the input list is empty, return an empty list.
  
  def remove_duplicates(my_list):
   return list(dict.fromkeys(my_list))
  
  assert remove_duplicates([1, 2, 3, 4, 3, 2, 1]) == [1, 2, 3, 4]
  assert remove_duplicates([1, 1, 1, 1]) == [1]
  assert remove_duplicates([5, 3, 6, 6, 7, 3, 5]) == [5, 3, 6, 7]
  assert remove_duplicates(["apple", "banana", "apple", "cherry"]) == ["apple", "banana", "cherry"]
  assert remove_duplicates([]) == []
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