Expert Python Programming - Third Edition

Beyond PEP 8 – Team-specific style guidelines

Despite providing a comprehensive set of style guidelines, PEP 8 still leaves some freedom for the developers. Especially in terms of nested data literals and multiline function calls that require long lists of arguments. Some teams may decide that they require additional styling rules and the best option is to formalize them in some kind of document that is available for every team member.

Also, in some situations, it may be impossible or economically infeasible to be strictly consistent with PEP 8 in some old projects that had no style guide defined. Such projects will still benefit from formalization of the actual coding conventions even if they do not reflect the official set of PEP 8 rules. ...