Functools – The Power of Higher-Order Functions in Python
The worst part of python is the lack of utility functions for munging collections. But it sits at a slightly higher level than this - things that are idiomatic in other scripting languages like groupBy(fn), sortBy(fn), countBy(fn), collate, are all inexplicably like IKEA self assembled furniture in Python instead of first class entities. It makes lots of routine data munging and algorithmic work much more annoying than it needs to be (comparing to Groovy, Ruby, etc).