code: def test_read_julia_notebook(
      markdown="""```julia
  1 + 1
  ```
  """,
  ):
      nb = jupytext.reads(markdown, "md")
      assert nb.metadata["jupytext"]["main_language"] == "julia"
      assert len(nb.cells) == 1
      assert nb.cells[0].cell_type == "code"
      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 5 for calling a global function with example usage: test_read_julia_notebook(markdown) without return types