How to use the publ.utils.file_fingerprint function in Publ

"""
        self.name = name

        # Flask expects template filenames to be /-separated regardless of
        # platform
        if os.sep != '/':
            self.filename = '/'.join(os.path.normpath(filename).split(os.sep))
        else:
            self.filename = filename

        self.file_path = file_path

        if file_path:
            self.mtime = os.stat(file_path).st_mtime
            self.last_modified = arrow.get(self.mtime)
            self._fingerprint = utils.file_fingerprint(file_path)

        self.content = content
        if content:
            self._fingerprint = hashlib.md5(content.encode('utf-8')).hexdigest()

def set_fingerprint(fullpath, fingerprint=None):
    """ Set the last known modification time for a file """
    try:
        fingerprint = fingerprint or utils.file_fingerprint(fullpath)

        record = model.FileFingerprint.get(file_path=fullpath)
        if record and record.fingerprint != fingerprint:
            record.set(fingerprint=fingerprint,
                       file_mtime=os.stat(fullpath).st_mtime)
        elif not record:
            record = model.FileFingerprint(
                file_path=fullpath,
                fingerprint=fingerprint,
                file_mtime=os.stat(fullpath).st_mtime)
        orm.commit()
    except FileNotFoundError:
        orm.delete(fp for fp in model.FileFingerprint if fp.file_path == fullpath)

def _get_asset(file_path):
    """ Get the database record for an asset file """
    record = model.Image.get(file_path=file_path)
    fingerprint = ','.join((utils.file_fingerprint(file_path),
                            str(RENDITION_VERSION)))
    if not record or record.fingerprint != fingerprint:
        # Reindex the file
        LOGGER.info("Updating image %s -> %s", file_path, fingerprint)

        # compute the md5sum; from https://stackoverflow.com/a/3431838/318857
        md5 = hashlib.md5()
        md5.update(bytes(RENDITION_VERSION))
        with open(file_path, 'rb') as file:
            for chunk in iter(lambda: file.read(16384), b""):
                md5.update(chunk)

        values = {
            'file_path': file_path,
            'checksum': md5.hexdigest(),
            'fingerprint': fingerprint,

def scan_file(fullpath: str, relpath: typing.Optional[str], fixup_pass: int) -> bool:
    """ scan a file and put it into the index

    :param fullpath str: The full file path
    :param relpath typing.Optional[str]: The file path relative to the content
        root; if None, this will be inferred
    :param fixup_pass int: Which iteration of fixing-up we're on

    """
    # pylint: disable=too-many-branches,too-many-statements,too-many-locals

    try:
        check_fingerprint = utils.file_fingerprint(fullpath)
        entry = load_message(fullpath)
    except FileNotFoundError:
        # The file doesn't exist, so remove it from the index
        record = model.Entry.get(file_path=fullpath)
        if record:
            expire_record(record)
        return True

    entry_id = get_entry_id(entry, fullpath, fixup_pass > 0)
    if entry_id is None:
        return False

    fixup_needed = False

    if not relpath:
        relpath = os.path.relpath(fullpath, config.content_folder)

def save_file(fullpath: str, entry: email.message.Message, fingerprint: str):
    """ Save a message file out, without mangling the headers """
    from atomicwrites import atomic_write
    with atomic_write(fullpath, overwrite=True) as file:
        # we can't just use file.write(str(entry)) because otherwise the
        # headers "helpfully" do MIME encoding normalization.
        # str(val) is necessary to get around email.header's encoding
        # shenanigans
        for key, val in entry.items():
            print(f'{key}: {str(val)}', file=file)
        print('', file=file)
        file.write(entry.get_payload())

        if utils.file_fingerprint(fullpath) != fingerprint:
            LOGGER.warning("File %s changed during atomic write; aborting", fullpath)
            raise RuntimeError("File changed during reindex")

    return True

def scan_directory(root, files):
        """ Helper function to scan a single directory """
        LOGGER.debug("scanning directory %s", root)
        try:
            for file in files:
                fullpath = os.path.join(root, file)
                relpath = os.path.relpath(fullpath, content_dir)

                if not is_scannable(fullpath):
                    continue

                fingerprint = utils.file_fingerprint(fullpath)
                last_fingerprint = get_last_fingerprint(fullpath)
                if fingerprint != last_fingerprint:
                    LOGGER.debug("%s: %s -> %s", fullpath, last_fingerprint, fingerprint)
                    indexer.scan_file(fullpath, relpath, 0, wait_start)
        except Exception:  # pylint:disable=broad-except
            LOGGER.exception("Got error parsing directory %s", root)

def _get_asset(file_path):
    """ Get the database record for an asset file """
    record = model.Image.get(file_path=file_path)
    fingerprint = ','.join((utils.file_fingerprint(file_path),
                            str(RENDITION_VERSION)))
    if not record or record.fingerprint != fingerprint:
        # Reindex the file
        logger.info("Updating image %s -> %s", file_path, fingerprint)

        # compute the md5sum; from https://stackoverflow.com/a/3431838/318857
        md5 = hashlib.md5()
        md5.update(bytes(RENDITION_VERSION))
        with open(file_path, 'rb') as file:
            for chunk in iter(lambda: file.read(16384), b""):
                md5.update(chunk)

        values = {
            'file_path': file_path,
            'checksum': md5.hexdigest(),
            'fingerprint': fingerprint,