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);