code: def shorter_name(key):
      
      key_short = key
      for sep in ['#', '/']:
          ind = key_short.rfind(sep)
          if ind is not None:
              key_short = key_short[ind+1:]
          else:
              key_short = key_short
      return key_short.replace('-', '_').replace('.', '_')
docs: Return a shorter name for an id.
  
      Does this by only taking the last part of the URI,
      after the last / and the last #. Also replaces - and . with _.
  
      Parameters
      ----------
      key: str
          Some URI
  
      Returns
      -------
      key_short: str
          A shortened, but more ambiguous, identifier