code: def _format_modified_time(timestamp: int) -> str:
      """Return an RFC 3339 formatted string representing the given timestamp."""
      seconds, fraction = divmod(timestamp, 10**6)
      return (
          time.strftime("%Y-%m-%d %H:%M:%S", time.gmtime(seconds))
          + f".{fraction // 1_000}"
      )
  
imports: from __future__ import annotations
  import functools
  import os
  import pickle
  import time
  from collections import defaultdict
  from copy import copy
  from os import path
  from typing import TYPE_CHECKING, Any, Callable, NoReturn
  from sphinx import addnodes
  from sphinx.environment.adapters import toctree
  from sphinx.errors import BuildEnvironmentError, DocumentError, ExtensionError, SphinxError
  from sphinx.locale import __
  from sphinx.transforms import SphinxTransformer
  from sphinx.util import DownloadFiles, FilenameUniqDict, logging
  from sphinx.util.docutils import LoggingReporter
  from sphinx.util.i18n import CatalogRepository, docname_to_domain
  from sphinx.util.nodes import is_translatable
  from sphinx.util.osutil import canon_path, os_path
label_desc: Use image node_id 2 for calling a global function with example usage: _format_modified_time(timestamp) and returns: unknown