code: def test_notebook_one_blank_line_before_first_markdown_cell(
      script="""
  # This is a markdown cell
  
  1 + 1
  """,
  ):
      notebook = jupytext.reads(script, "py")
      script2 = jupytext.writes(notebook, "py")
      compare(script2, script)
  
      assert len(notebook.cells) == 3
      for cell in notebook.cells:
          lines = cell.source.splitlines()
          if len(lines):
              assert lines[0]
              assert lines[-1]
  
imports: import pytest
  from nbformat.v4.nbbase import new_code_cell, new_markdown_cell, new_notebook, new_raw_cell
  import jupytext
  from jupytext.compare import compare, compare_notebooks
label_desc: Use image node_id 29 for calling a global function with example usage: test_notebook_one_blank_line_before_first_markdown_cell(script) without return types