input: def print_checkerboard(size: int) -> None:
      """Prints a checkerboard pattern of a given size. The size determines the dimensions
      of the board, with each cell being either a '#' or a space. Cells containing '#'
      are determined by whether the sum of the cell's row and column indices is even.
      >>> print_checkerboard(1)
  
      >>> print_checkerboard(2)
      # 
       #
      >>> print_checkerboard(3)
      # #
       # 
      # #
      """
      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()