anchor.diff:  #
   # https://jupyterlab.readthedocs.io/en/stable/user/jupyterhub.html
   # https://nbconvert.readthedocs.io/en/latest/install.html#installing-nbconvert
  +
  +# https://www.kdnuggets.com/2020/07/apache-spark-cluster-docker.html
   
   # Jupyter Hub Dockerfile 
   #
  
positive.code: 
  RUN python3 -m pip install jupyterlab
  RUN python3 -m pip install ipywidgets
  
  RUN pip3 install jupyter-tensorboard
  
  
negative.code: #ENV DEBIAN_FRONTEND noninteractive 
  ENV INITRD No
  #ENV LANG en_US.UTF-8
  ENV JUPYTER_VERSION 2.1.5 
  ENV SPARK_VERSION 3.0.0
  
  LABEL Name="Jupyter for CRE" \
        CRE=$CRE_VERSION \ 
  