This chapter started with topic differences between Python 2 and 3 with advice on how to deal with the current situation where a big part of its community is torn between two worlds. Then, it came to the modern approaches to Python development that were surprisingly developed mostly due to this unfortunate split between two major versions of the language. These are mostly different solutions to the environment isolation problem. The chapter ended with a short summary of the popular productivity tools as well as popular resources for further reference.