anchor.diff:  
   # Install and hold a specific version of RabbitMQ
   RUN \
  -    apt-get -y --no-install-recommends install "rabbitmq-server=3.8.9-1" && \
  +    apt-get -y --no-install-recommends install "rabbitmq-server=3.8.12-1" && \
       apt-mark hold rabbitmq-server && \
       rm -rf /etc/rabbitmq/ && \
       true
  
positive.code: # and check "apt-cache policy erlang-nox | rabbitmq-server" for available
  # versions)
  RUN \
      export ERLANG_APT_PACKAGE_VERSION="1:23.1.4-1" && \
      apt-get -y --no-install-recommends install \
          "erlang-asn1=$ERLANG_APT_PACKAGE_VERSION" \
          "erlang-base=$ERLANG_APT_PACKAGE_VERSION" \
  
negative.code: 
  # Add RabbitMQ APT repository
  RUN \
      #
      # Erlang
      curl -fsSL https://packages.erlang-solutions.com/ubuntu/erlang_solutions.asc | apt-key add - && \
      echo "deb https://packages.erlang-solutions.com/ubuntu focal contrib" \
          > /etc/apt/sources.list.d/rabbitmq-erlang.list && \
      #
      # RabbitMQ
      curl -fsSL https://packagecloud.io/rabbitmq/rabbitmq-server/gpgkey | apt-key add - && \
      echo "deb https://packagecloud.io/rabbitmq/rabbitmq-server/ubuntu focal main" \
          > /etc/apt/sources.list.d/rabbitmq.list && \
      #
      apt-get -y update && \
      true
  
  