input: Write a function to create a TicTacToe game in Python. The function should return an instance of the TicTacToe class, which should have methods to initialize the board, display the current board state, and check if the current player has won.
  
  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
  
          for row in self.board:
              if row.count(self.turn) == 3:
                  return True
          
          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
          
          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 type(TicTacToe()) == TicTacToe
  assert TicTacToe().check_win() == False
  assert TicTacToe().board == [['_', '_', '_'], ['_', '_', '_'], ['_', '_', '_']]
output: 
  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
  
          for row in self.board:
              if row.count(self.turn) == 3:
                  return True
          
          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
          
          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
  