input: def print_chessboard(size: int) -> None:
      """Prints a chessboard pattern of the given size.
      Examples:
      >>> print_chessboard(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()