input: Write a function to remove duplicates from a list and return the list sorted in ascending order. If the input list is empty, return an empty list.
  
  def remove_duplicates(my_list):
   return sorted(list(dict.fromkeys(my_list)))
  
  assert remove_duplicates([1, 2, 3, 4, 3, 2, 1])==[1, 2, 3, 4]
  assert remove_duplicates([5, 4, 5, 6, 7, 4, 5])==[4, 5, 6, 7]
  assert remove_duplicates([])==[]
  assert remove_duplicates([1])==[1]
  assert remove_duplicates([3, 3, 3, 3, 3])==[3]
output: def remove_duplicates(my_list):
      return sorted(list(dict.fromkeys(my_list)))