def help(self, msg):
        """
        help [command] - displays available commands, or help message for given command
        """
        commands = {}
        for handler in self.irc.handlers:
            if isinstance(handler, CommandHandler):
                for command in handler.triggers:
                    method = getattr(handler, command)
                    if hasattr(method, '__doc__') and method.__doc__:
                        commands[command] = method.__doc__.strip()
                    else:
                        commands[command] = 'No help available for command: %s' % command

        if len(msg.args) == 2:
            if msg.args[1] not in commands:
                message = 'Unknown command: %s' % msg.args[1]
            else:
                message = commands[msg.args[1]]
        else:
            message = 'Available commands: %s' % ', '.join(commands.keys())

        if msg.event == EVT_PUBLIC:
            self.irc.msg(msg.dst, message)
        elif msg.event == EVT_PRIVATE:
            self.irc.msg(msg.src, message)
        elif msg.event == EVT_NOTICE:
            self.irc.notice(msg.src, message)
help [command] - displays available commands, or help message for given command