docs: def olderado_best_model(pdb_id):
      """ Checks the Olderado web server and returns the most representative conformation for PDB NMR structures.
  
      Notes
      -----
      Uses OLDERADO from the EBI.
      See http://www.ebi.ac.uk/pdbe/nmr/olderado/ and citations therein.
  
      Parameters
      ----------
      pdb_id : str
          The 4-character PDB code for the NMR structure of interest.
  
      Returns
      -------
      model_no : int
          The conformation number of the most-representative conformation.
  
      Raises
      ------
      ValueError
          If the model number it finds is not an integer. This might indicate that the website format has changed.
      """
      pdb_code = pdb_id[:4].lower()
      olderado_url = 'http://www.ebi.ac.uk/pdbe/nmr/olderado/searchEntry?pdbCode=' + pdb_code
      olderado_page = download_decode(olderado_url, verbose=False)
      if olderado_page:
          parsed_page = BeautifulSoup(olderado_page, 'html.parser')
      else:
          return None
      try:
          best_model = parsed_page.find_all('td')[1]
      except IndexError:
          print("No model info could be found for {0} - ensure that it's an NMR structure.".format(pdb_id))
          return None
      try:
          model_no = int(best_model.string)
      except ValueError as v:
          print("Did not find a number for best model.")
          raise v
      return model_no