small details

[michael135]

Yam, I enjoy your notebooks!

small details which might be updated:

1. I'm not sure that Convolution2s is used in last version of keras. I believe it should be Conv2d

2. in 2.2.3 it should be $(k, k, n_i, n_o)$ instead of $(n_o, n_i, k, k)$
   @ypeleg