anchor.diff:      source activate $PYTHON_2_ENV && \
       pip install --quiet -U --upgrade-strategy only-if-needed --no-cache-dir \
           apache-airflow==1.9.0 \
  +        apache-beam[gcp]==2.7.0 \
           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 \
  
positive.code:         pygments==2.1.3 \
          python-dateutil==2.5.0 \
          python-snappy==0.5.1 \
          pytz==2016.7 \
          pyzmq==17.1.0 \
          requests==2.18.4 \
          scikit-image==0.13.0 \
  
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 \
  