为什么要在'play_data'中反转输入特征？

为什么要在'play_data'中反转 input features？

play_data 1:
```
[[0,0,0], [0,1,0], [0,0,0]] # white
[[0,0,0], [0,0,0], [0,0,0]] # black
[[0,0,0], [0,1,0], [0,0,0]] # action
[[0,0,0], [0,0,0], [0,0,0]] # player
```

play_data 2:
```
[[1,0,0], [0,0,0], [0,0,0]] # black
[[0,0,0], [0,1,0], [0,0,0]] # white
[[1,0,0], [0,0,0], [0,0,0]] # action
[[1,1,1], [1,1,1], [1,1,1]] # player
```

