code: def test_simple_notebook_is_trusted(tmpdir, python_notebook):
      cm = TextFileContentsManager()
      cm.root_dir = str(tmpdir)
  
      nb = python_notebook
      cm.notary.unsign(nb)
  
      # All cells are trusted in this notebook
      assert cm.notary.check_cells(nb)
      # Yet the notebook is not in the database of trusted notebooks
      assert not cm.notary.check_signature(nb)
  
      # Save the notebook using the CM
      cm.save(dict(type="notebook", content=nb), "test.ipynb")
  
      # The notebook is safe so it should have been trusted before getting saved to disk
      nb = cm.get("test.ipynb")["content"]
      assert cm.notary.check_signature(nb)
  
file_path: jupytext/tests/functional/others/test_trust_notebook.py
imports: import os
  import shutil
  import pytest
  from nbformat.v4.nbbase import new_code_cell, new_output
  from jupytext.compare import compare_notebooks
  from jupytext.contentsmanager import TextFileContentsManager
label_desc: Use image node_id 6 for calling a global function with example usage: test_simple_notebook_is_trusted(tmpdir, python_notebook) without return types