input: Write a function to implement a TicTacToe game in Python. The function should include methods to initialize the game board, display the board, and check if the current player has won the game. The game board is a 3x3 grid and players take turns to place their symbol ('x' or 'o') until one player wins or the board is full.
  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().check_win() == False
  assert TicTacToe().check_win() == False
  assert TicTacToe().check_win() == False
  assert TicTacToe().check_win() == False
  assert TicTacToe().check_win() == False
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