[BUG] Change condition in Filters.user to avoid error with empty lists #1562
Description
Consider changing this condition
python-telegram-bot/telegram/ext/filters.py
Line 796 in 88eccc6
to something like
if (user_id is None) == (username is None):To avoid throwing the ValueError "One and only one of user_id or username must be used" when an empty list of user_ids or usernames is issued.
Similarly for Filters.chat.
PS This should also be 3 to 4 times faster.