docs: def execute(self, env, args):
          """ Displays task time left in minutes.
  
              `env`
                  Runtime ``Environment`` instance.
              `args`
                  Arguments object from arg parser.
              """
  
          msg = u'Time Left: {0}m' if not args.short else '{0}'
          mins = max(0, self.total_duration - env.task.duration)
          env.io.write(msg.format(mins))