input: Write a response that appropriately completes the given TicTacToe game in Python, including an implementation for the `move` and `is_draw` methods. The `move` method should update the board with the player's move and alternate the turn, while the `is_draw` method should return `True` if the board is full and no player has won yet.
  
  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
  
      def move(self, row, col):
          if self.board[row][col] == '_':
              self.board[row][col] = self.turn
              if self.turn == 'x':
                  self.turn = 'o'
              else:
                  self.turn = 'x'
              return True
          return False
  
      def is_draw(self):
          for row in self.board:
              if '_' in row:
                  return False
          return True
  
  assert TicTacToe().move(0, 0) == True
  assert TicTacToe().move(0, 0) == False
  assert TicTacToe().is_draw() == False
  assert TicTacToe().move(0, 1) == True
  assert TicTacToe().move(1, 1) == True
  assert TicTacToe().move(0, 2) == True
output: def move(self, row, col):
      if self.board[row][col] == '_':
          self.board[row][col] = self.turn
          if self.turn == 'x':
              self.turn = 'o'
          else:
              self.turn = 'x'
          return True
      return False
  
  def is_draw(self):
      for row in self.board:
          if '_' in row:
              return False
      return True