old_contents: # This program emulates a tic-tac-toe board
  theBoard = {'top-L': ' ', 'top-M': ' ', 'top-R': ' ',
              'mid-L': ' ', 'mid-M': ' ', 'mid-R': ' ',
              'low-L': ' ', 'low-M': ' ', 'low-R': ' '}
  
  
  def printBoard(board):
      print(board['top-L'] + '|' + board['top-M'] + '|' + board['top-R'])
      print('-+-+-')
      print(board['mid-L'] + '|' + board['mid-M'] + '|' + board['mid-R'])
      print('-+-+-')
      print(board['low-L'] + '|' + board['low-M'] + '|' + board['low-R'])
  
  
  turn = 'X'
  for i in range(9):
      printBoard(theBoard)
      print('Turn for ' + turn + '. Move on which space?')
      move = input()
      theBoard[move] = turn
      if turn == 'X':
          turn = 'O'
      else:
          turn = 'X'
  printBoard(theBoard)
  
new_contents: """Tic Tac Toe
  
  This program plays a game of tic-tac-toe using a :obj:`dict` to store the board.
  
  Attributes:
      theBoard (dict): Dictionary containing the current status of the tic-tac-toe board.
  
  Note:
      * Space names are defined as follows::
      
          top-L | top-M | top-R
          ------+-------+------
          mid-L | mid-M | mid-R
          ------+-------+------
          low-L | low-M | low-R
  
      * Intended for two players.
  
  """
  
  theBoard = {'top-L': ' ', 'top-M': ' ', 'top-R': ' ',
              'mid-L': ' ', 'mid-M': ' ', 'mid-R': ' ',
              'low-L': ' ', 'low-M': ' ', 'low-R': ' '}
  
  
  def printBoard(board: dict) -> None:
      """Print board
      
      Prints each row of a given tic-tac-toe board.
      
      Args:
          board:  Dictionary containing space names as keys and contents as values.
  
      Returns:
          None. Prints rows of tic-tac-toe board.
      """
      print(board['top-L'] + '|' + board['top-M'] + '|' + board['top-R'])
      print('-+-+-')
      print(board['mid-L'] + '|' + board['mid-M'] + '|' + board['mid-R'])
      print('-+-+-')
      print(board['low-L'] + '|' + board['low-M'] + '|' + board['low-R'])
  
  
  def main():    
      turn = 'X'
      """char: Player's marker, either `X` or `O`"""
  
      for i in range(9):
          printBoard(theBoard)
          print('Turn for ' + turn + '. Move on which space?')
          move = input()
          theBoard[move] = turn
          if turn == 'X':
              turn = 'O'
          else:
              turn = 'X'
      printBoard(theBoard)
  
  
  if __name__ == '__main__':
      main()
  
subject: Update P04_ticTacToe.py added docstrings and wrapped in main() function