anchor.diff:     $(lsb_release -cs) \
      stable"
   
  -RUN apt-get update && apt-get install -y docker-ce
  +RUN apt-get update \
  +  && apt-get install -y --no-install-recommends \
  +    docker-ce \
  +  && apt-get clean autoclean \
  +  && apt-get autoremove -y \
  +  && rm -rf /var/lib/apt/lists/* \
  +  && rm -f /var/cache/apt/archives/*.deb
   
   CMD ["python3.6"]
  
positive.code: # Install dependencies.
  RUN apt-get update \
    && apt-get install -y --no-install-recommends \
      build-essential \
      bzip2 \
      ca-certificates \
      git \
      libbz2-dev \
      libreadline-dev \
      libsqlite3-dev \
      libssl-dev \
      ssh \
      tcl \
      tcl-dev \
      tk \
  
negative.code:   virtualenv
  
  # Install docker
  RUN curl -fsSL https://download.docker.com/linux/ubuntu/gpg | sudo apt-key add -
  
  RUN add-apt-repository \
  