Python style guide

Pigweed uses the standard Python style: PEP8. All Pigweed Python code should pass pw format, which invokes black with a couple options.

Python versions

Pigweed officially supports a few Python versions. Upstream Pigweed code must support those Python versions. The only exception is pw_env_setup, which must also support Python 2 and 3.6.

Extend the import path of packages with generated files

Python packages that include generated files should extend their import path using the following snippet at the beginning of their __init__.py:

# This Python package contains generated Python modules that overlap with
# this `__init__.py` file's import namespace, so this package's import path
# must be extended for the generated modules to be discoverable.
#
# Note: This needs to be done in every nested `__init__.py` that will contain
# overlapping generated files.
__path__ = __import__('pkgutil').extend_path(__path__, __name__)