code: def _format_final_exc_line(etype, value):
      
      valuestr = _some_str(value)
      if value is None or not valuestr:
          line = "%s\n" % etype
      else:
          line = "%s: %s\n" % (etype, valuestr)
      return line
docs: Return a list of a single line -- normal case for format_exception_only