This docker file demonstrates a seeming bug with pylint==2.6.1

Dockerfile

# docker build -t binesh/pylint-bug .
# docker run --rm binesh/pylint-bug python3.8 -m pylint -r n /tmp/demo1.py
# docker run --rm binesh/pylint-bug python3.8 -m pylint -r n /tmp/demo2.py
FROM python:3.8

MAINTAINER Binesh Bannerjee <binesh_binesh@hotmail.com>

RUN /usr/local/bin/python3.8 -m pip install -U pylint==2.6.1

RUN echo "def func(blah):" > /tmp/demo1.py && \
    echo "    assert "x" not in blah or blah["x"] is None" >> /tmp/demo1.py

RUN echo "def div6():" > /tmp/demo2.py && \
    echo "    return [num for num in sorted([1, 2, 3, 4]) if (num % 2 == 0) and (num % 3 == 0)]" >> /tmp/demo2.py

RUN /usr/local/bin/python3.8 -m pip freeze

CMD ["/usr/local/bin/python3.8", "-m", "pylint", "-r", "n", "/tmp/demo1.py"]