Egor Emelin

I checked the code and it seems that `self._sender = self.client._sender` should be ` self._sender = self._client._sender` in https://github.com/LonamiWebs/Telethon/blob/a0e42c1eb7b884c2247cf845bc2acbf545563f50/telethon/client/downloads.py#L57 I ran code with this modification. The above exception resolves but...