def make_rerunner_prep_dockerfile(self, docker_file, existing_image):
        self.setup_lines()
        docker_lines = [
              "FROM {0}".format(existing_image)
            , "RUN mkdir -p /{0}".format(self.shared_name)
            , "RUN {0}".format(self["move_into_volume"])
            , "VOLUME /{0}".format(self.shared_name)
            ]
        return DockerFile(docker_lines=docker_lines, mtime=docker_file.mtime)
Given an existing image:
dataset/ETHPy150Open realestate-com-au/harpoon/harpoon/option_spec/image_objs.py/Persistence.make_rerunner_prep_dockerfile