input: 
  class TicTacToe:
      """Create a TicTacToe game in Python.
      The game should initialize with an empty 3x3 board and start with 'x' as the first player.
      The display method should print the current state of the board.
      The check_win method should return True if the current player has won the game, otherwise False.
      
      Example:
      game = TicTacToe()
      game.display()
      >>> _ _ _
      >>> _ _ _
      >>> _ _ _
  
      game.board = [['x', '_', '_'], ['x', '_', '_'], ['x', '_', '_']]
      game.check_win()
      >>> True
      """
  
output:     
      def __init__(self):
          self.board = [['_' for _ in range(3)] for _ in range(3)]
          self.current_player = 'x'
  
      def display(self):
          for row in self.board:
              print(' '.join(row))
  
      def check_win(self):
          # Check rows
          for row in self.board:
              if row[0] == row[1] == row[2] != '_':
                  return True
          
          # Check columns
          for col in range(3):
              if self.board[0][col] == self.board[1][col] == self.board[2][col] != '_':
                  return True
          
          # Check diagonals
          if self.board[0][0] == self.board[1][1] == self.board[2][2] != '_':
              return True
          if self.board[0][2] == self.board[1][1] == self.board[2][0] != '_':
              return True
          
          return False
  