anchor.diff:  
   # Install system requirements
   RUN apt-get update && \
  +    apt-get install -y software-properties-common && \
  +    apt-add-repository -y ppa:deadsnakes/ppa && apt-get update && \
       # Global requirements
       DEBIAN_FRONTEND=noninteractive apt-get install --yes \
       build-essential \
  
positive.code: ENV SETTINGS production
  RUN mkdir -p /edx/etc/
  
  # Install Python requirements
  RUN pip install pip==20.0.2
  COPY setup.py setup.py
  COPY common common
  COPY openedx openedx
  
negative.code:     libxslt1-dev \
      ntp \
      pkg-config \
      python3.8-dev \
      python3.8-venv \
      &&rm -rf /var/lib/apt/lists/*
  
  RUN locale-gen en_US.UTF-8
  ENV LANG en_US.UTF-8
  ENV LANGUAGE en_US:en
  ENV LC_ALL en_US.UTF-8
  
  WORKDIR /edx/app/edxapp/edx-platform
  
  