input: Write a function named remove_duplicates that takes a list as an input and returns a new list with all duplicate elements removed. The returned list should keep the order of elements as they appear in the input list.
  
  
  def remove_duplicates(my_list):
      return list(dict.fromkeys(my_list))
  
  my_list = [1, 2, 3, 4, 3, 2, 1]
  
  print(remove_duplicates(my_list))  # output [1, 2, 3, 4]
  
output: def remove_duplicates(my_list):
      return list(dict.fromkeys(my_list))