I've done:
mysql_tzinfo_to_sql /usr/share/zoneinfo | mysql -u root mysql
As per:
mysql> select count(*) from `mysql`.`time_zone_name`;
+----------+
| count(*) |
+----------+
| 1778 |
+----------+
And my env has pytz:
$ pip list | grep pytz
pytz (2014.2)
But I'm still getting
ValueError: Database returned an invalid value in QuerySet.datetimes(). Are time zone definitions for your database and pytz installed?
What could be the cause?