Update documentation, errors and add TODOs

telethon/client/account.py

@@ -6,6 +6,8 @@ from .. import utils
 from ..tl import functions, TLRequest
 
 
+# TODO Make use of :tl:`InvokeWithMessagesRange` somehow
+#      For that, we need to use :tl:`GetSplitRanges` first.
 class _TakeoutClient:
     """
     Proxy object over the client.

telethon/client/telegrambaseclient.py

@@ -23,6 +23,7 @@ __default_log__ = logging.getLogger(__base_name__)
 __default_log__.addHandler(logging.NullHandler())
 
 
+# TODO How hard would it be to support both `trio` and `asyncio`?
 class TelegramBaseClient(abc.ABC):
     """
     This is the abstract base class for the client. It defines some