code: def notebook_object_to_rst(ntbk, rpth, cr=None):
      
  
      # Parent directory of file rpth
      rdir = os.path.dirname(rpth)
      # File basename
      rb = os.path.basename(os.path.splitext(rpth)[0])
  
      # Pre-process notebook prior to conversion to rst
      if cr is not None:
          preprocess_notebook(ntbk, cr)
      # Convert notebook to rst
      rex = RSTExporter()
      rsttxt, rstres = rex.from_notebook_node(ntbk)
      # Replace `` with ` in sphinx cross-references
      rsttxt = re.sub(r':([^:]+):``(.*?)``', r':\1:`\2`', rsttxt)
      # Insert a cross-reference target at top of file
      reflbl = '.. _examples_' + os.path.basename(rdir) + '_' + \
               rb.replace('-', '_') + ':\n'
      rsttxt = reflbl + rsttxt
      # Write the converted rst to disk
      write_notebook_rst(rsttxt, rstres, rb, rdir)
docs: Convert notebook object `ntbk` to rst document at `rpth`, in
      directory `rdir`.  Parameter `cr` is a CrossReferenceLookup
      object.