code: def extract_from_plain(msg_body):
      
      stripped_text = msg_body
  
      delimiter = get_delimiter(msg_body)
      msg_body = preprocess(msg_body, delimiter)
      # don't process too long messages
      lines = msg_body.splitlines()[:MAX_LINES_COUNT]
      markers = mark_message_lines(lines)
      lines = process_marked_lines(lines, markers)
  
      # concatenate lines, change links back, strip and return
      msg_body = delimiter.join(lines)
      msg_body = postprocess(msg_body)
      return msg_body
docs: Extracts a non quoted message from provided plain text.