code: def default(self, argv):
          
          errmsg = self._str(self.unknowncmd % (argv[0], ))
          if self.cmdlooping:
              self.stderr.write(errmsg + "\n")
          else:
              self.stderr.write("%s: %s\nTry '%s help' for info.\n" %
                                (self._name_str, errmsg, self._name_str))
          self.stderr.flush()
          return 1
docs: Hook called to handle a command for which there is no handler.
  
              "argv" is the command and arguments to run.
  
          The default implementation writes an error message to stderr
          and returns an error exit status.
  
          Returns a numeric command exit status.