anchor.diff:      libxslt1.1 \
       libxslt1-dev \
       libyaml-dev \
  +    m4 \
       nginx \
       openssh-client \
       python-dev \
  
positive.code: 
  
  # install Tosca engine
  RUN apt-get install -y m4
  RUN pip install python-dateutil
  RUN bash /opt/xos/tosca/install_tosca.sh
  
  # configure nginx
  
negative.code:     django-ipware \
      django-encrypted-fields \
      django_rest_swagger \
      python-dateutil \
      python-keyczar \
      pygraphviz \
      dnslib \
  