I wrote a simple TicTacToe console game in Python3. I would like to make my program more pythonic than it is now. For example, instead of if a == 5 and b == 5 and c == 5: you can write if a == b == c == 5:. So I expect hints of how can I rewrite my code to take adventage of Python language.

I don’t ask for algorithm optimization (it contains some bugs, I know). The code should be rather understood for you except computer_turn() method which simulates computer’s move. But since I don’t ask for optimization I don’t see a need to explain what exacly happens inside this method.

You may find my code on Github.

from random import randint, choice import time, sys, os  class TicTacToe:     board = [None for i in range(9)] # list representing game's board      turn = 1 # counter of computer's turns       def print_board(self, board = None): # printing game board          board = self.board if board == None else board          os.system("clear") # use "cls" for windows         print("|---|---|---|")         for i, cell in enumerate(board, 1):             print("| {} ".format(" " if cell == None else cell), end = "")             if i % 3 == 0:                 print("|")                 print("|---|---|---|")       def get_game_winner(self, board = None):         board = self.board if board == None else board          for i in range(0, 9, 3):             if board[i] == board[i + 1] == board[i + 2]:                 if board[i] != None: return board[i]          for i in range(0, 3):             if board[i] == board[i + 3] == board[i + 6]:                 if board[i] != None: return board[i]          if board[0] == board[4] == board[8] or board[2] == board[4] == board[6]:             if board[4] != None: return board[4]          return None       def computer_turn(self):         position = None          def get_line(cell):             if cell <= 3: return 1             if cell <= 6: return 2             return 3          if self.turn == 1:             self.turn = 2             oponent_choice = self.board.index("X")             if oponent_choice + 1 in [1, 3, 7, 9]:                 position = 5 - 1             else:                 position = choice([1, 3, 7, 9]) - 1          elif self.turn == 2:             self.turn = 3             for i in [1, 3, 7, 9]:                 if self.board[i - 1] == "X":                     if self.board[5 - 1] == "X":                         position = 10 - i - 1                         if self.board[position] == "O":                             position = choice([item - 1 for item in [1, 3, 7, 9] if item not in [position + 1, i]])                         break                      for j in [1, 3, 7, 9]:                         if i != j and self.board[j - 1] == "X":                             position = i + (j - i) // 2 - 1                             if self.board[position] == "O":                                 position = choice([2, 4, 6, 8]) - 1                             break                      for j in [2, 4, 6, 8]:                         if self.board[j - 1] == "X":                             diff = abs(j - i)                             if get_line(i) != get_line(j) and diff == 1:                                 position = 5 - 1                             else:                                 position = max(i, j) + diff                                 if position > 9: position = min(i, j) - diff                                 if self.board[position - 1] == "O": position = 5                                 position -= 1               if position == None:                 for i in [2, 4, 6, 8]:                     if self.board[i - 1] == "X":                         if self.board[5 - 1] == "X":                             position = 10 - i - 1                         else:                             position = 5 - 1          if self.turn > 2:             tmp_board = self.board[:]             candidates = [i for i in range(9) if self.board[i] == None]             for candidate in candidates:                 tmp_board[candidate] = "O"                 if self.get_game_winner(tmp_board) == "O":                     position = candidate                     break                 tmp_board[candidate] = None              if position == None:                 for candidate in candidates:                     tmp_board[candidate] = "X"                     if self.get_game_winner(tmp_board) == "X":                         position = candidate                         break                     tmp_board[candidate] = None              if position == None: position = candidates[0]           self.board[position] = "O"       def ask_for_choice(self):         while True:             try:                 print("Your choice: ", end = "")                 position = int(input())             except ValueError:                 print("That's not an integer!")                 continue              if 1 <= position <= 9:                 return position - 1             else:                 print("Number must be in range 1 to 9!")       def user_turn(self):         position = self.ask_for_choice()          while self.board[position] != None:             print("This position is filled")             position = self.ask_for_choice()          self.board[position] = "X"       def is_game_finished(self):         if None not in self.board:             print("The game ended with a draw")             sys.exit()          winner = self.get_game_winner()         if winner == None: return          if winner == "X": print("You won the game!")         else: print("Computer won the game")         sys.exit()       def start(self):         self.print_board([i for i in range(1, 10)])         print()         print("Hello, the game just started!")         while True:              self.user_turn()             self.print_board()             self.is_game_finished()              time.sleep(0.5)             self.computer_turn()             self.print_board()             self.is_game_finished()   game = TicTacToe() game.start()