Flake8

Flake8 is a Python library that wraps PyFlakes, pycodestyle and Ned Batchelder’s McCabe script. It is a great toolkit for checking your codebase against coding style (PEP8), programming errors (like “library imported but unused” and “Undefined name”) and to check cyclomatic complexity.

If you are not familiar with the term cyclomatic complexity, it is a software metric created by Thomas J. McCabe to measure the number of independent paths through the source code. Generally speaking, the higher number of ifs inside a function, the higher number of paths it will have, thus a higher cyclomatic complexity. Of course, there are other control flow operations that impact the calculus of the cyclomatic complexity. It is also referred to as McCabe complexity.

For further details visit https://flake8.pycqa.org/en/latest/index.html

Installation

$ poetry add flake8 --dev

Configuration

Create a setup.cfg file and add the following:

[flake8]
max-line-length = 88
max-complexity = 10
show-source = true
extend-ignore = E203, W503
per-file-ignores =
    # imported but unused
    __init__.py: F401

Usage

$ flake8 python_lifecycle tests

Next Step

To move on to the next step commit or stash your changes then checkout to the branch init/format/black

$ git stash
$ git checkout init/format/black

Uninstall

$ poetry remove flake8 --dev