anchor.diff:  WORKDIR ${HOME}
   
   
  -# Install notebook extensions
  -#RUN pip install --user --no-cache-dir \
  -    #jupyter \
  -    #jupyter_contrib_nbextensions \
  -    #jupyterhub-legacy-py2-singleuser==0.7.2
  -
   RUN git clone https://github.com/ipython-contrib/jupyter_contrib_nbextensions.git
  +RUN pip install ipywidgets
   RUN pip install --user -e jupyter_contrib_nbextensions
   
   ENV PATH ${PATH}:/home/jovyan/.local/bin
  
positive.code: 
  FROM clawpack/v5.6.0_dockerimage:release
  # this dockerhub image has a user jovyan and clawpack installed 
  # in /home/jovyan/clawpack-v5.6.0
  
  
  ENV NB_USER jovyan
  
negative.code: 
  RUN pip install --user --no-cache-dir -r $HOME/riemann_book/requirements.txt
  
  # The command below starts the notebook server, but better to not
  # do this by default in case the user also wants to examine files or use
  # the docker container for running other things...
  #CMD jupyter notebook riemann_book/Index.ipynb --ip=0.0.0.0 --port=8889 --no-browser
  
  