docs: def make_code_obsolete(code):
      """ Moves folders associated with PDB code to obsolete folder in global_settings["database_dir"]
  
      Parameters
      ----------
      code : str
          PDB accession code
  
      Returns
      -------
      None
      """
      fs = FileSystem(code=code)
      if os.path.exists(fs.parent_dir):
          # Move to obsolete folder
          destination_dir = os.path.join(fs._data_dir, 'obsolete', code[1:3], code)
          if os.path.exists(destination_dir):
              shutil.rmtree(destination_dir)
          shutil.move(fs.parent_dir, destination_dir)
  
          # Remove containing (two-letter) folder if empty, else pass.
          two_letter_dir = os.path.dirname(fs.parent_dir)
          try:
              os.rmdir(two_letter_dir)
          except OSError:
              pass
  
      return