public static async Task <IEnumerable <IGroupChannel> > GetGroupChannelsAsync(this IDiscordClient client) => (await client.GetPrivateChannelsAsync().ConfigureAwait(false)).OfType <IGroupChannel>();
public static async Task <IEnumerable <IGroupChannel> > GetGroupChannelsAsync(this IDiscordClient client) => (await client.GetPrivateChannelsAsync().ConfigureAwait(false)).Select(x => x as IGroupChannel).Where(x => x != null);