code: def test_read_simple_code(
      no_jupytext_version_number,
      ml="""(* %% *)
  let sum x y = x + y
  """,
      nb=new_notebook(
          cells=[
              new_code_cell("""let sum x y = x + y"""),
          ]
      ),
  ):
      nb2 = jupytext.reads(ml, "ml:percent")
      compare_notebooks(nb2, nb)
      ml2 = jupytext.writes(nb, "ml:percent")
      compare(ml2, ml)
  
imports: from nbformat.v4.nbbase import new_code_cell, new_markdown_cell, new_notebook
  import jupytext
  from jupytext.compare import compare, compare_notebooks
label_desc: Use image node_id 1 for calling a global function with example usage: test_read_simple_code(no_jupytext_version_number, ml, nb) without return types