input: 
  class TicTacToe:
      """Create a TicTacToe game in Python. 
      The game board is a 3x3 grid and players 'x' and 'o' alternate turns.
      The game tracks the current state of the board and checks for a win condition.
  
      Example:
      >>> game = TicTacToe()
      >>> game.display()
      _ _ _
      _ _ _
      _ _ _
      """
  
      def __init__(self):
          self.board = [['_' for _ in range(3)] for _ in range(3)]
          self.turn = 'x'
  
      def display(self):
          for row in self.board:
              print(' '.join(row))
  
      def check_win(self):
          board = self.board
  
          # check if the player with the current turn has a row of three
          for row in self.board:
              if row.count(self.turn) == 3:
                  return True
  
          # check if the player with the current turn has a column of three
          for col in range(3):
              if board[0][col] == board[1][col] and board[1][col] == board[2][col] and board[2][col] == self.turn:
                  return True
  
          # check for the two diagonals
          if board[0][0] == board[1][1] and board[1][1] == board[2][2] and board[2][2] == self.turn:
              return True
          if board[0][2] == board[1][1] and board[1][1] == board[2][0] and board[2][0] == self.turn:
              return True
          return False
  
output:     def make_move(self, row, col):
          if self.board[row][col] == '_':
              self.board[row][col] = self.turn
              if self.check_win():
                  print(f"Player {self.turn} wins!")
              self.turn = 'o' if self.turn == 'x' else 'x'
          else:
              print("Invalid move, try again.")
  
      def is_full(self):
          for row in self.board:
              if '_' in row:
                  return False
          return True