code: def test_pep8():
      text = """import os
  
  path = os.path
  
  
  # code cell #1, with a comment on f
  def f(x):
      return x + 1
  
  
  # markdown cell #1
  
  # code cell #2 - an instruction
  a = 4
  
  
  # markdown cell #2
  
  # code cell #3 with a comment on g
  def g(x):
      return x + 1
  
  
  # markdown cell #3
  
  # the two lines are:
  # - right below the function/class
  # - below the last python paragraph (i.e. NOT ABOVE g)
  
  # code cell #4
  x = 4
  """
      nb = reads(text, "py")
      for cell in nb.cells:
          assert not cell.metadata
  
      text2 = writes(nb, "py")
      compare(text2, text)
  
file_path: jupytext/tests/unit/test_pep8.py
imports: from nbformat.v4.nbbase import new_code_cell, new_notebook
  from jupytext import read, reads, writes
  from jupytext.compare import compare
  from jupytext.pep8 import cell_ends_with_code, cell_ends_with_function_or_class, cell_has_code, next_instruction_is_function_or_class, pep8_lines_between_cells
label_desc: Use image node_id 7 for calling a global function with example usage: test_pep8() without return types