anchor.diff:  # acknowledge the contributions of their colleagues of the SONATA
   # partner consortium (www.sonata-nfv.eu).
   
  -FROM python:3.4-slim
  +FROM python:3.5-slim
   MAINTAINER SONATA
   
   # configrurations
  
positive.code: # install package dependencies
  RUN apt-get clean \
      && apt-get update \
      && apt-get install -y git build-essential libffi-dev libssl-dev
  
  # clone son-sm repo to install dependencies
  RUN git clone --recursive https://github.com/sonata-nfv/son-sm.git
  
negative.code: RUN python setup.py install
  
  # run fsm
  COPY . /vpn-config/
  
  WORKDIR /vpn-config
  RUN python setup.py develop
  