Lint is the common name used to the Static Program Analysis process witch consists on an automated scan of your source code in search of bad practicies or misuse of code conventions.
There are several sets of linting rules for every program language. For Python theese rules are defiened in a document called PEP8.
The more rules better results, so a good start point is the Pylama package that combines several linters together.
To understand python linter I suggest you to read the article "Python Code Quality" at realpython.com/python-code-quality/
See the example below:
FROM cytopia/docker-pylint:latest as linter
COPY s rc /data
RUN pylint /data
...
FROM python:3.8-slim as production
COPY src /app
USER app
CMD["python", "/app/start.py"]In this Dockerfile we are using two images. The lint image and a python for production. The images are both used to create containers but only the last image will be used to create the final image.