def _can_obtain_door(content):
    """
    Check if the explored cards can obtain a door.
    """
    last_card = content.explored[-1]
    same_count = 0
    for card in reversed(content.explored):
        if last_card.color == card.color:
            same_count += 1
        else:
            break
    return same_count % 3 == 0