anchor.diff:  #  install the packages necessary to build Python source:
   RUN apt update && apt install -y build-essential zlib1g-dev libncurses5-dev libgdbm-dev \
       libnss3-dev libssl-dev libreadline-dev libffi-dev libbz2-dev \
  -    libncursesw5-dev libsqlite3-dev tk-dev libc6-dev ca-certificates
  +    libncursesw5-dev libsqlite3-dev tk-dev libc6-dev ca-certificates \
  +    && apt-get clean \
  +    && rm -rf /var/lib/apt/lists/*
   
  -# downland Python soruce code
  -RUN curl -O https://www.python.org/ftp/python/3.7.8/Python-3.7.8.tar.xz \
  -    && tar -xf Python-3.7.8.tar.xz \
  -    && rm -f Python-3.7.8.tar.xz
  -
  -# build and install Python
  -RUN cd Python-3.7.8 \
  +# downland and install Python from soruce code
  +RUN PYTHON_VERSION="3.7.8" \
  +    && curl -O https://www.python.org/ftp/python/$PYTHON_VERSION/Python-$PYTHON_VERSION.tar.xz \
  +    && tar -xf Python-$PYTHON_VERSION.tar.xz \
  +    && rm -f Python-$PYTHON_VERSION.tar.xz \
  +    && cd ./Python-$PYTHON_VERSION \
       && ./configure --enable-optimizations \
  -    && make -j `nproc` \
  +    && make -j $(nproc) \
       && make install \
       && cd .. \
  -    && rm -rf Python-3.7.8 \
  +    && rm -rf ./Python-$PYTHON_VERSION \
       && ln -s /usr/local/bin/pip3.7 /usr/local/bin/pip \
       && ln -s /usr/local/bin/python3.7 /usr/local/bin/python
   
  
positive.code: RUN apt-get update \
      && curl -sL https://deb.nodesource.com/setup_8.x | bash - \
      && apt-get install -y \
          nodejs
  
  # install database clients for debugging (https://www.postgresql.org/download/linux/debian/)
  RUN echo "deb http://apt.postgresql.org/pub/repos/apt $(lsb_release -cs)-pgdg main" > /etc/apt/sources.list.d/pgdg.list \
  
negative.code:     && apt-get update && apt-get install -y \
          gcc \
          libpq-dev \
      && apt-get clean \
      && rm -rf /var/lib/apt/lists/* \
      && pip install gsutil
  
  RUN CLOUDSDK_CORE_DISABLE_PROMPTS=1 \
  