Fix SenderGetter should not define abstract methods
Fix SenderGetter should not define abstract methods

Or at least it shouldn't if subclasses are likely to not
implement them, which causes an error if left un-implemented.

LonamiWebs/Telethon,LonamiWebs/Telethon,expectocode/Telethon,LonamiWebs/Telethon,LonamiWebs/Telethon