def METHOD_NAME(self):
    """
    Will create a manifest file if it doesn't exists.
    :return:
    """
    if self.file_manager.file_exist(self._get_manifest_file_path()):
        msg = "File %s already exists." % self._get_manifest_file_path()
        raise BackupManifestException(msg)
    self._create_files_metadata()
    str_manifest = self._get_manifest_str()
    # Create checksum from string without last '}' and ',' instead
    manifest_checksum = self.checksum_algorithm.checksum_from_str(str_manifest)
    last_line = '"Manifest-Checksum": "%s"}\n' % manifest_checksum
    full_manifest = str_manifest + last_line
    self.file_manager.save_content_to_file(
        self._get_manifest_file_path(), full_manifest.encode(), file_mode="wb"
    )