input: 
  class TicTacToe:
      """Create a TicTacToe game in Python.
      The game is played on a 3x3 grid. Each player takes turns placing their
      marker ('x' or 'o') on the grid. The player who succeeds in placing
      three of their marks in a horizontal, vertical, or diagonal row wins
      the game. The game starts with 'x' as the first player.
      
      >>> game = TicTacToe()
      >>> game.board
      [['_', '_', '_'], ['_', '_', '_'], ['_', '_', '_']]
      >>> game.turn
      'x'
      >>> game.display()
      _ _ _
      _ _ _
      _ _ _
      >>> game.check_win()
      False
      """
  
      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():
                  return f"{self.turn} wins!"
              self.turn = 'o' if self.turn == 'x' else 'x'
          else:
              return "Invalid move"
  
      def is_full(self):
          return all(cell != '_' for row in self.board for cell in row)
  
      def reset(self):
          self.board = [['_' for _ in range(3)] for _ in range(3)]
          self.turn = 'x'