Confusing sentence in chapter 10

[netzzwergeGithub]

Hi,
with the sentence
' Let's say we want a batch size of 6.'
I had the expectation that each batch would be of the length of 6.
but the code creates 6 batches.

Later the text says it as it is:
'Going back to our previous example with 6 batches of length 15'

Martin