input: Write a function to remove duplicates from a list. The function should return a new list with all unique elements in the same order as they first appeared in the input list. If the input list is empty, the function should 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([5, 5, 6, 6, 7, 8, 7])==[5, 6, 7, 8] 
  assert remove_duplicates([1, 1, 1, 1, 1])==[1]
  assert remove_duplicates([])==[]
output: def remove_duplicates(my_list):
      return list(dict.fromkeys(my_list))