class_docstr: Track the current and nested state of the parser.
  
  This utility class is used to track the state of the `BlockParser` and
  support multiple levels if nesting. It's just a simple API wrapped around
  a list. Each time a state is set, that state is appended to the end of the
  list. Each time a state is reset, that state is removed from the end of
  the list.
  
  Therefore, each time a state is set for a nested block, that state must be
  reset when we back out of that level of nesting or the state could be
  corrupted.
  
  While all the methods of a list object are available, only the three
  defined below need be used.
docstr: Step back one step in nested state. 
docstr_tok: ["Step","back","one","step","in","nested","state","."]
code: def reset(self) -> None:
      """Step back one step in nested state."""
      self.pop()
  
file_path: markdown/markdown/blockparser.py
imports: from __future__ import annotations
  import xml.etree.ElementTree
  from typing import TYPE_CHECKING, Iterable, Any
  from .None import util
label_desc: Use image node_id 2 for calling the State obj's underlying member method code with example usage: obj.reset() without return types