code: def isurl(url: str) -> bool:
      """Check *url* is URL or not."""
      return bool(url) and "://" in url
  
imports: from __future__ import annotations
  import hashlib
  import os
  import posixpath
  import re
  from importlib import import_module
  from os import path
  from typing import IO, Any
  from urllib.parse import parse_qsl, quote_plus, urlencode, urlsplit, urlunsplit
  from sphinx.errors import ExtensionError, FiletypeNotFoundError
  from sphinx.locale import __
  from sphinx.util import display
  from sphinx.util import exceptions
  from sphinx.util import http_date
  from sphinx.util import index_entries
  from sphinx.util import logging
  from sphinx.util import osutil
  from sphinx.util.console import strip_colors
  from sphinx.util.matching import patfilter
  from sphinx.util.nodes import caption_ref_re, explicit_title_re, nested_parse_with_titles, split_explicit_title
  from sphinx.util.osutil import SEP, copyfile, copytimes, ensuredir, make_filename, mtimes_of_files, os_path, relative_uri
label_desc: Use image node_id 8 for calling a global function with example usage: isurl(url) and returns: unknown