code: def test_csharp_magics(no_jupytext_version_number, lang):
      md = """```{lang}
  #!html
  <b>Hello!</b>
  ```
  """.format(
          lang=lang
      )
      nb = jupytext.reads(md, "md")
      nb.metadata["jupytext"].pop("notebook_metadata_filter")
      nb.metadata["jupytext"].pop("cell_metadata_filter")
      assert nb.metadata["jupytext"]["main_language"] == "csharp"
      assert len(nb.cells) == 1
      assert nb.cells[0].cell_type == "code"
  
      cs = jupytext.writes(nb, "cs")
      assert all(line.startswith("//") for line in cs.splitlines()), cs
  
      md2 = jupytext.writes(nb, "md")
      md_expected = """---
  jupyter:
    jupytext:
      main_language: csharp
  ---
  
  ```html
  <b>Hello!</b>
  ```
  """
      compare(md2, md_expected)
  
imports: import pytest
  import jupytext
  from jupytext.compare import compare
label_desc: Use image node_id 2 for calling a global function with example usage: test_csharp_magics(no_jupytext_version_number, lang) without return types