class_docstr: Add various extensions to Markdown class.
class_docstr_tok: ["Add","various","extensions","to","Markdown","class","."]
docstr: Register extension instances. 
docstr_tok: ["Register","extension","instances","."]
code: def extendMarkdown(self, md):
      """Register extension instances."""
      md.registerExtensions(extensions, self.config)
  
imports: from __future__ import annotations
  from .None import Extension
label_desc: Use image node_id 2 for calling the ExtraExtension obj's underlying member method code with example usage: obj.extendMarkdown(md) without return types