code: def test_identity_source_write_read(py_file):
      with open(py_file) as fp:
          py = fp.read()
  
      nb = jupytext.reads(py, "py")
      py2 = jupytext.writes(nb, "py")
  
      compare(py2, py)
  
label_desc: Use image node_id 1 for calling a global function with example usage: test_identity_source_write_read(py_file) without return types