Validation error in `SlashCommandBuilder.addSubcommand`

registry.registerChatInputCommand(
            (builder) =>
                builder
            .setName('leaderboards') //
            .setDescription('Manage leaderboards.')
            .setDMPermission(false)
            .setDefaultMemberPermissions(PermissionFlagsBits.ManageChannels)
            .addSubcommand(
                new SlashCommandSubcommandBuilder() //
                .setName('deploy')
                .setDescription('Deploys a leaderboard of a given metric in this channel.')
                .addStringOption(
                    new SlashCommandStringOption() //
                    .setName('metric')
                    .setDescription("The leaderboard's tracked metric type.")
                    .setRequired(true)
                    .setChoices<APIApplicationCommandOptionChoice<LeaderboardType>>([
                        {
                            name: 'Appointments Set',
                            value: LeaderboardType.AppointmentsSet
                        },
                        {
                            name: 'Showed Up To Appointments',
                            value: LeaderboardType.ShowedUpToAppointments
                        },
                        {
                            name: 'Sequence Subscriptions',
                            value: LeaderboardType.SequenceSubscriptions
                        },
                        {
                            name: 'Completed Calls',
                            value: LeaderboardType.CompletedCalls
                        }
                    ])
                )
            )
        );