input: Write a Python program that removes duplicates from a list.
  
  def remove_duplicates(my_list):
   return list(dict.fromkeys(my_list))
  
  my_list = [1, 2, 3, 4, 3, 2, 1]
  
  assert remove_duplicates([1, 2, 3, 4, 3, 2, 1]) == [1, 2, 3, 4]
  assert remove_duplicates([5, 5, 5, 5, 5]) == [5]
  assert remove_duplicates([1, 2, 3, 4, 5]) == [1, 2, 3, 4, 5]
  assert remove_duplicates([]) == []
output: def remove_duplicates(my_list):
      return list(dict.fromkeys(my_list))