How to use the tern.utils.general function in tern

def setup(dockerfile=None, image_tag_string=None):
    '''Any initial setup'''
    # generate random names for image, container, and tag
    general.initialize_names()
    # load the cache
    cache.load()
    # load dockerfile if present
    if dockerfile:
        dhelper.load_docker_commands(dockerfile)
    # check if the docker image is present
    if image_tag_string:
        if not container.check_image(image_tag_string):
            # if no docker image is present, try to pull it
            if not container.pull_image(image_tag_string):
                logger.fatal("%s", errors.cannot_find_image.format(
                    imagetag=image_tag_string))
                sys.exit()
    # create temporary working directory
    if not os.path.exists(constants.temp_folder):
        os.mkdir(constants.temp_folder)

def generate_yaml(images):
    '''Generate a yaml report'''
    logger.debug('Creating YAML report...')
    report = formats.disclaimer_yaml.format(
        version_info=general.get_git_rev_or_version())
    for image in images:
        report = report + content.print_yaml_report(image)
    return report

def get_version():
    '''Return the version string for the --version command line option'''
    ver_type, commit_or_ver = general.get_git_rev_or_version()
    message = ''
    if ver_type == "package":
        message = "Tern version {}".format(commit_or_ver)
    else:
        message = "Tern at commit {}".format(commit_or_ver)
    return message

def create_top_dir():
    '''Create the top level working directory'''
    top_dir = general.get_top_dir()
    if not os.path.isdir(top_dir):
        os.mkdir(top_dir)

def get_shell_commands(shell_command_line):
    '''Given a shell command line, get a list of Command objects'''
    comm_list = general.split_command(shell_command_line)
    cleaned_list = []
    for comm in comm_list:
        cleaned_list.append(Command(general.clean_command(comm)))
    return cleaned_list

def get_shell_commands(shell_command_line):
    '''Given a shell command line, get a list of Command objects'''
    comm_list = general.split_command(shell_command_line)
    cleaned_list = []
    for comm in comm_list:
        cleaned_list.append(Command(general.clean_command(comm)))
    return cleaned_list

def extract_image_metadata(image_tag_string):
    '''Run docker save and extract the files in a temporary directory'''
    temp_path = rootfs.get_working_dir()
    placeholder = os.path.join(general.get_top_dir(), temp_tarfile)
    try:
        if common.check_tar(image_tag_string) is True:
            # image_tag_string is the path to the tar file for raw images
            rootfs.extract_tarfile(image_tag_string, temp_path)
        else:
            image = client.images.get(image_tag_string)
            result = image.save(chunk_size=2097152, named=True)
            # write all of the tar byte stream into temporary tar file
            with open(placeholder, 'wb') as f:
                for chunk in result:
                    f.write(chunk)
            # extract tarfile into folder
            rootfs.extract_tarfile(placeholder, temp_path)
            # remove temporary tar file
            os.remove(placeholder)
        if not os.listdir(temp_path):