code: def emph(txt, rval=None):
      
  
      if rval is None:    # rval is not specified, use 'neutral'
          info(txt)
      elif rval == 0:     # rval is 0, by convention, this is 'good'
          good(txt)
      else:               # any other value, considered 'bad'
          err(txt)
docs: Print, emphasized based on rval