anchor.diff:          six==1.11.0 \
           statsmodels==0.8.0 \
           sympy==0.7.6.1 \
  -        tornado==4.4.2 \
  +        tornado==4.5.1 \
           xgboost==0.6a2 && \
   # Install Python3 packages that aren't available or up-to-date in Conda.
       source activate $PYTHON_3_ENV && \
  
positive.code: # Set up Python 3.5 Conda env and install packages.
      conda create --yes --quiet --name $PYTHON_3_ENV python=3.5 \
          crcmod==1.7 \
          google-api-python-client==1.6.2 \
          httplib2==0.10.3 \
          h5py==2.7.1 \
  
negative.code:         six==1.11.0 \
          statsmodels==0.8.0 \
          sympy==0.7.6.1 \
          tornado==4.5.1 \
          xgboost==0.6a2 && \
  # Install Python2 packages that aren't available or up-to-date in Conda.
      source activate $PYTHON_2_ENV && \
  