def add(self, subcmd_cb):
subcmd_name = subcmd_cb.name<EOL>self.subcmds[subcmd_name] = subcmd_cb<EOL>self.cmdlist.append(subcmd_name)<EOL>
Add subcmd to the available subcommands for this object.
        It will have the supplied docstring, and subcmd_cb will be called
        when we want to run the command. min_len is the minimum length
        allowed to abbreviate the command. in_list indicates with the
        show command will be run when giving a list of all sub commands
        of this object. Some commands have long output like "show commands"
        so we might not want to show that.