class_docstr: Parser base class which provides some common support methods used
  by the SGML/HTML and XHTML parsers.
code: def __init__(self):
      if self.__class__ is ParserBase:
          raise RuntimeError(
              "_markupbase.ParserBase must be subclassed"
          )
  
file_path: cpython/Lib/_markupbase.py
imports: import re
label_desc: Use image node_id 1 to create a new ParserBase object  with example: obj = ParserBase()