anchor.diff:          pygments==2.1.3 \
           python-dateutil==2.5.0 \
           python-snappy==0.5.1 \
  -        pytz==2016.7 \
  +        pytz==2018.4 \
           pyzmq==17.1.0 \
           requests==2.18.4 \
           scikit-image==0.13.0 \
  
positive.code:     source activate $PYTHON_2_ENV && \
      pip install --quiet -U --upgrade-strategy only-if-needed --no-cache-dir \
          apache-airflow==1.9.0 \
          bs4==0.0.1 \
          ggplot==0.6.8 \
          google-cloud-dataflow==2.0.0 \
          google-cloud-monitoring==0.28.0 \
          lime==0.1.1.23 \
          protobuf==3.5.2 \
  
negative.code:         pygments==2.1.3 \
          python-dateutil==2.5.0 \
          python-snappy==0.5.1 \
          pytz==2018.4 \
          pyzmq==17.1.0 \
          requests==2.18.4 \
          scikit-image==0.13.0 \
  