anchor.diff:  RUN source activate py3 && conda install -c conda-forge jupyterlab -y
   
   # Integration between jupyterhub and jupyterlab
  -RUN jupyter labextension install @jupyterlab/hub-extension
  +# not working: https://github.com/jupyterhub/jupyterlab-hub/issues/78
  +#RUN jupyter labextension install @jupyterlab/hub-extension
   
   # Support for other languages
   # https://github.com/jupyter/jupyter/wiki/Jupyter-kernels
  
positive.code: 
  # Libreoffice - https://www.libreoffice.org/download/libreoffice-fresh/
  # Linux x64 rpm
  ENV LIBREOFFICE_VER 6.1.2
  ENV LIBREOFFICE_VER_MINOR .1
  
  RUN wget http://mirror.nbtelecom.com.br/tdf/libreoffice/stable/$LIBREOFFICE_VER/rpm/x86_64/LibreOffice_${LIBREOFFICE_VER}_Linux_x86-64_rpm.tar.gz \
  	&& echo "b462407ca869da19c387d4349e51cf7a  LibreOffice_${LIBREOFFICE_VER}_Linux_x86-64_rpm.tar.gz" > LIBREOFFICEMD5 \
  	&& RESULT=$(md5sum -c LIBREOFFICEMD5) \
  	&& echo ${RESULT} > ~/check-libreoffice-md5.txt \
  	&& tar xf LibreOffice_${LIBREOFFICE_VER}_Linux_x86-64_rpm.tar.gz \
  	&& cd LibreOffice_${LIBREOFFICE_VER}${LIBREOFFICE_VER_MINOR}_Linux_x86-64_rpm/RPMS \
  	&& yum -y install *.rpm \
  	&& yum clean all \
  	&& cd && rm -f LIBREOFFICEMD5 && rm -f LibreOffice_${LIBREOFFICE_VER}_Linux_x86-64_rpm.tar.gz \
  	&& rm -rf LibreOffice_${LIBREOFFICE_VER}${LIBREOFFICE_VER_MINOR}_Linux_x86-64_rpm
  
  # Shiny - https://www.rstudio.com/products/shiny/download-server/
  ENV SHINY_VER 1.5.9.923
  
negative.code: # https://repo.continuum.io/archive
  ENV CONDA_VER 5.3.0
  
  ENV PATH $PATH:/usr/local/conda/anaconda3/bin
  
  RUN wget https://repo.continuum.io/archive/Anaconda3-$CONDA_VER-Linux-x86_64.sh \
  	&& bash Anaconda3-$CONDA_VER-Linux-x86_64.sh -b -p /usr/local/conda/anaconda3 \
  	&& rm -f Anaconda3-$CONDA_VER-Linux-x86_64.sh \
  	&& conda update -n base conda -y
  
  # Install py2 and py3 envs, and registers jupyterhub kernels
  # https://github.com/jupyter/jupyter/issues/71
  