input: from typing import List
  
  
  def print_checkerboard(size: int) -> None:
      """
      Print a square checkerboard pattern of the given size. Each cell
      will either print a '#' or a space character. The cell (i, j) is
      '#' if (i + j) % 2 == 0, otherwise it is a space character.
  
      >>> print_checkerboard(7)
      # # # # # # #
       # # # # # # #
      # # # # # # #
       # # # # # # #
      # # # # # # #
       # # # # # # #
      # # # # # # #
      """
      for i in range(size):
          for j in range(size):
              if (i + j) % 2 == 0:
                  print('#', end='')
              else:
                  print(' ', end='')
          print()
output:     for i in range(size):
          for j in range(size):
              if (i + j) % 2 == 0:
                  print('#', end='')
              else:
                  print(' ', end='')
          print()