code: def deregister_image(self, ami_id, region='us-east-1'):
          
          deregister_cmd = "aws ec2 --profile {} --region {} deregister-image --image-id {}"\
              .format(self.aws_project, region, ami_id)
          print "De-registering old image, now that the new one exists."
          print "De-registering cmd: {}".format(deregister_cmd)
          res = subprocess.check_output(shlex.split(deregister_cmd))
          print "Response: {}".format(res)
          print "Not monitoring de-register command"
docs: Deregister an AMI by id
          :param ami_id:
          :param region: region to deregister from
          :return: