Simple tic tac toe game

tictactoe.py

# -*- coding: utf-8 -*-

GRID = {
    1: 1,
    2: 2,
    3: 3,
    4: 4,
    5: 5,
    6: 6,
    7: 7,
    8: 8,
    9: 9,
}


WINNER_RESULTS = [
    [1, 2, 3],
    [1, 4, 7],
    [1, 5, 9],
    [3, 5, 7],
    [4, 5, 6],
    [2, 5, 8],
    [7, 8, 9],
    [3, 6, 9],
]


def check_winner(player):
    for result in WINNER_RESULTS:
        if all(GRID[x] == player for x in result):
            return True


def check_game_over():
    return all(type(x) is not int for x in GRID.values())


def mark_player_move(player, position):
    GRID[position] = player


def point_repr(val):
    if val is True:
        return "✗"
    if val is False:
        return "●"
    return val


def get_grid_repr():
    return """
    -------------
    | {} | {} | {} |
    -------------
    | {} | {} | {} |
    -------------
    | {} | {} | {} |
    -------------
    """.format(*[point_repr(x) for x in GRID.values()])


if __name__ == '__main__':
    current_player = True  # 2 players: True or False
    while True:
        print(get_grid_repr())
        move = int(input("Select free a position: "))
        mark_player_move(current_player, move)
        if check_winner(current_player):
            print("Player {} has won!".format(point_repr(current_player)))
            break
        if check_game_over():
            print("Draw")
            break
        current_player = not current_player