    # File lib/rbot/ircbot.rb, line 1231
      def help(topic=nil)
        topic = nil if topic == ""
        case topic
        when nil
          helpstr = _("help topics: ")
          helpstr += @plugins.helptopics
          helpstr += _(" (help <topic> for more info)")
        else
          unless(helpstr = @plugins.help(topic))
            helpstr = _("no help for topic %{topic}") % { :topic => topic }
          end
        end
        return helpstr
      end