code: def myst_extensions(no_md=False):
      """The allowed extensions for the myst format."""
      if no_md:
          return [".myst", ".mystnb", ".mnb"]
      return [".md", ".myst", ".mystnb", ".mnb"]
  
imports: import json
  import re
  import warnings
  from textwrap import dedent
  import nbformat
  import yaml
  from .cell_to_text import three_backticks_or_more
label_desc: Use image node_id 4 for calling a global function with example usage: myst_extensions(no_md) and returns: list, list