anchor.diff:  # Stick with jpeg 8 to avoid problems with R packages
   RUN echo "jpeg 8*" >> /opt/conda/conda-meta/pinned
   
  +# Install JupyterHub to get the jupyterhub-singleuser startup script
  +RUN pip --no-cache-dir install 'jupyterhub==0.5'
  +
   # Install Python 3 packages
   # Remove pyqt and qt pulled in for matplotlib since we're only ever going to
   # use notebook-friendly backends in these images
   RUN conda install --quiet --yes \
  -    'ipywidgets=5.1*' \
       'pandas=0.18*' \
       'numexpr=2.5*' \
       'matplotlib=1.5*' \
  
positive.code:     'numba=0.23*' \
      'bokeh=0.11*' \
      'h5py=2.5*' && \
      conda remove --quiet --yes --force qt pyqt && \
      conda clean -tipsy
  # Activate ipywidgets extension in the environment that runs the notebook server
  
negative.code:     'bokeh=0.11*' \
      'h5py=2.5*' \
      'pyzmq' && \
      conda install -c conda-forge -p $CONDA_DIR/envs/python2 python=2.7 ipywidgets && \
      conda remove -n python2 --quiet --yes --force qt pyqt && \
      conda clean -tipsy
  
  # Add shortcuts to distinguish pip for python2 and python3 envs
  RUN ln -s $CONDA_DIR/envs/python2/bin/pip $CONDA_DIR/bin/pip2 && \
      ln -s $CONDA_DIR/bin/pip $CONDA_DIR/bin/pip3
  