input: from typing import List
  
  def optimize_printing(numbers: List[int]) -> None:
      """ Optimize the given program to print all elements in the list once, each on a new line.
      >>> numbers = [1, 2, 3, 4, 5, 6]
      >>> optimize_printing(numbers)
      1
      2
      3
      4
      5
      6
      """
output:     for num in numbers:
          print(num)