class_docstr: Override `HTMLExtractor` and create `etree` `Elements` for any elements which should have content parsed as
  Markdown.
docstr: Reset this instance.  Loses all unprocessed data.
code: def reset(self):
      """Reset this instance.  Loses all unprocessed data."""
      self.mdstack: list[
          str
      ] = []  # When markdown=1, stack contains a list of tags
      self.treebuilder = etree.TreeBuilder()
      self.mdstate: list[Literal["block", "span", "off", None]] = []
      super().reset()
  
imports: from __future__ import annotations
  from .None import Extension
  from ..blockprocessors import BlockProcessor
  from ..preprocessors import Preprocessor
  from ..postprocessors import RawHtmlPostprocessor
  from ..None import util
  from ..htmlparser import HTMLExtractor, blank_line_re
  import xml.etree.ElementTree
  from typing import TYPE_CHECKING, Literal, Mapping
label_desc: Use image node_id 2 for calling the HTMLExtractorExtra obj's underlying member method code with example usage: obj.reset() without return types