ormalization.inverse and BatchNormalization.forward are not
guaranteed to be inverses of each other because <code>inverse(y)</code> uses statistics of the current minibatch,
while <code>forward(x)</code> uses running-average statistics accumulated from training.
In other words, <code>tfb_batch_normalization()$inverse(tfb_batch_normalization()$forward(...))</code> and
<code>tfb_batch_normalization()$forward(tfb_batch_normalization()$inverse(...))</code> will be identical when
training=FALSE but may be differ