code: def to_xhtml_string(element: Element) -> str:
      """Serialize element and its children to a string of XHTML."""
      return _write_html(ElementTree(element).getroot(), format="xhtml")
  
file_path: markdown/markdown/serializers.py
imports: from __future__ import annotations
  from xml.etree.ElementTree import ProcessingInstruction
  from xml.etree.ElementTree import Comment, ElementTree, Element, QName, HTML_EMPTY
  import re
  from typing import Callable, Literal, NoReturn
label_desc: Use image node_id 8 for calling a global function with example usage: to_xhtml_string(element) and returns: _write_html