public async Task Ban(Group group, MessageChain who, string reason)
{
var at = (At)who.FirstOrDefault(x => x is At);
if (at != null)
{
_service.Ban(at.TargetId, reason);
await group.SendPlainAsync($"{at.TargetId} has been banned: {reason}.");
}
}
public static void Ban(this User user, string reason)
{
service.Ban(user.Identity, reason);
}