I will not argue the first point, but as for the second one: how does that one author determine what is 'the Pythonic way'? I think

  [sum(week) for week in partition(7, 7, daily)]

is 'the Pythonic way' and I find that quite a bit easier to comprehend than

  map(sum, partition(7, 7, daily))

The reason for that is as simple as it runs counter to what people usually preach: it is less concise. In the former, it is immediately clear that you are partitioning a list of days into partitions of weeks and summing over those weeks, resulting in a list of weekly sums. The extra word 'week', repeated twice, makes all the difference: all ingredients for comprehension are readily provided. The latter case, on the contrary, requires you to do a few mental operations to expand the expression into something meaningful, mentally adding the concept of a 'week' to understand what the code is doing. You need to do that everytime you read the code, which makes it less easy to understand.