code: def test_pipe_into_flake8():
      # Notebook OK
      nb = new_notebook(cells=[new_code_cell("# correct code\n1 + 1")])
      pipe_notebook(nb, "flake8", update=False)
  
      # Notebook not OK
      nb = new_notebook(cells=[new_code_cell("incorrect code")])
      with pytest.raises(SystemExit):
          pipe_notebook(nb, "flake8", update=False)
  
imports: import os
  from copy import deepcopy
  from shutil import copyfile
  import pytest
  from nbformat.v4.nbbase import new_code_cell, new_notebook
  from jupytext import read, write
  from jupytext.cli import jupytext, pipe_notebook, system
  from jupytext.combine import black_invariant
  from jupytext.compare import compare, compare_cells, compare_notebooks
  from jupytext.header import _DEFAULT_NOTEBOOK_METADATA
label_desc: Use image node_id 5 for calling a global function with example usage: test_pipe_into_flake8() without return types