code: def markdown_cell(md):
      """Create a markdown cell with md inside."""
      return nbformat.notebooknode.NotebookNode(
          {"cell_type": "markdown", "source": md, "metadata": {}}
      )
  
imports: import nbformat
  import os
  import re
  import shutil
label_desc: Use image node_id 13 for calling a global function with example usage: markdown_cell(md) and returns: nbformat