anchor.diff:  
   WORKDIR $HOME
   USER $NB_USER
  +
  +# Copy notebooks into place
  +COPY . $HOME
   
   # Note: this Dockerfile is ordered roughly by how often things are expected
   # to change (ascending). That way, only the last few changed steps are
  
positive.code: RUN pip3 install --no-cache-dir pandeia.engine==$PANDEIA_VERSION
  
  # Extract Pandeia reference data into $HOME/pandeia_wfirst_data
  ADD pandeia_wfirst_data.tar.gz
  RUN tar xvz pandeia_wfirst_data.tar.gz
  ENV pandeia_refdata $HOME/pandeia_wfirst_data
  
  
negative.code: # Prepare files and permissions
  #
  
  # As root, adjust permissions on notebooks
  USER root
  RUN chown -Rv $NB_USER:users $HOME/*.ipynb
  