class_docstr: Add various extensions to Markdown class.
class_docstr_tok: ["Add","various","extensions","to","Markdown","class","."]
docstr: `config` is a dumb holder which gets passed to the actual extension later. 
docstr_tok: ["`","config","`","is","a","dumb","holder","which","gets","passed","to","the","actual","extension","later","."]
code: def __init__(self, **kwargs):
      """`config` is a dumb holder which gets passed to the actual extension later."""
      self.config = kwargs
  
imports: from __future__ import annotations
  from .None import Extension
label_desc: Use image node_id 1 to create a new ExtraExtension object from inherited base classes: Extension with example: obj = ExtraExtension()