code: def extract(body, sender):
      
      try:
          delimiter = get_delimiter(body)
  
          body = body.strip()
  
          if has_signature(body, sender):
              lines = body.splitlines()
  
              markers = _mark_lines(lines, sender)
              text, signature = _process_marked_lines(lines, markers)
  
              if signature:
                  text = delimiter.join(text)
                  if text.strip():
                      return (text, delimiter.join(signature))
      except Exception as e:
          log.exception('ERROR when extracting signature with classifiers')
  
      return (body, None)
docs: Strips signature from the body of the message.
  
      Returns stripped body and signature as a tuple.
      If no signature is found the corresponding returned value is None.