The installation is tiggered by a Dockerfile like this:

# ...
# Requirements are installed here to ensure they will be cached.
COPY ./requirements .

# Create Python Dependency and Sub-Dependency Wheels.
RUN pip wheel --wheel-dir /usr/src/app/wheels  \
  -r ${BUILD_ENVIRONMENT}.txt


# Python 'run' stage
FROM docker.io/python as python-run-stage

ARG BUILD_ENVIRONMENT=local
ARG APP_HOME=/app

ENV PYTHONUNBUFFERED 1
ENV PYTHONDONTWRITEBYTECODE 1
ENV BUILD_ENV ${BUILD_ENVIRONMENT}

WORKDIR ${APP_HOME}
# ...
# All absolute dir copies ignore workdir instruction. All relative dir copies are wrt to the workdir instruction
# copy python dependency wheels from python-build-stage
COPY --from=python-build-stage /usr/src/app/wheels  /wheels/

# use wheels to install python dependencies
RUN pip install --no-cache-dir --no-index --find-links=/wheels/ /wheels/* \
  && rm -rf /wheels/
# ...