code: def test_read_markdown_file_no_language(
      markdown="""```
  ls
  ```
  
  ```
  echo 'Hello World'
  ```
  """,
  ):
      nb = jupytext.reads(markdown, "md")
      markdown2 = jupytext.writes(nb, "md")
      compare(markdown2, markdown)
  
imports: from nbformat.v4.nbbase import new_code_cell, new_markdown_cell, new_notebook, new_raw_cell
  import jupytext
  from jupytext.combine import combine_inputs_with_outputs
  from jupytext.compare import compare, compare_cells, compare_notebooks
label_desc: Use image node_id 4 for calling a global function with example usage: test_read_markdown_file_no_language(markdown) without return types