code: def test_cell_metadata_filter_is_updated():
      text = """---
  jupyter:
    jupytext:
      cell_metadata_filter: -all
  ---
  
  ```{r cache=FALSE}
  1+1
  ```
  """
      nb = reads(text, "Rmd")
      assert (
          nb.metadata["jupytext"]["cell_metadata_filter"]
          == "cache,-all"
      )
  
      text2 = writes(nb, "Rmd")
      assert text.splitlines()[-3:] == text2.splitlines()[-3:]
  
imports: from copy import deepcopy
  import pytest
  from nbformat.v4.nbbase import new_code_cell, new_notebook
  from jupytext import reads, writes
  from jupytext.cli import jupytext
  from jupytext.compare import compare, compare_notebooks
  from jupytext.metadata_filter import filter_metadata, metadata_filter_as_dict
label_desc: Use image node_id 8 for calling a global function with example usage: test_cell_metadata_filter_is_updated() without return types