input: from typing import List
  
  def print_unique(my_list: List[int]) -> None:
      """Print each unique element of a given list only once.
      >>> print_unique([1, 1, 2, 3, 4, 2, 5])
      1
      2
      3
      4
      5
      """
output:     seen = set()
      for item in my_list:
          if item not in seen:
              print(item)
              seen.add(item)