anchor.diff:  #
   # Pandoc filters
   #
  -RUN pip2 --no-cache-dir install \
  +RUN pip3 --no-cache-dir install \
  +        panflute \
           pandocfilters \
  +        pandoc-latex-admonition \
           pandoc-latex-environment \
           pandoc-latex-barcode \
           pandoc-latex-levelup \
  
positive.code:         pypdf2 \
          ${NULL-}
  
  # planflute does not like python2
  RUN pip3 --no-cache-dir install panflute \
  		 pandoc-latex-admonition
  
  # Entrypoint
  VOLUME /pandoc
  WORKDIR /pandoc
  ENTRYPOINT ["pandoc"]
  
negative.code:         # build tools
          git \
          parallel \
          wget \
          # panflute requirements
          python3-pillow \
          python3-pip \
          python3-setuptools \
          python3-wheel \
          python3-yaml \
          # required for PDF meta analysis
          poppler-utils \
          zlibc \
      # clean up
      && apt-get clean && \
      rm -rf /var/lib/apt/lists/* /etc/apt/apt.conf.d/01proxy
  