input: Write a function to create a TicTacToe game in Python. The function should include an initialization method that sets up the game board and specifies whose turn it is, a method to display the board, and a method to check if the current player has won the game. The function should return the class definition.
  
  class TicTacToe:
  
  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
  
  assert TicTacToe().display() == "\n".join(['_ _ _', '_ _ _', '_ _ _'])
  assert TicTacToe().check_win() == False
  assert TicTacToe().turn == 'x'
output: 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