Despite cassandra_connection.connected being True getting CQLEngineException about django-cassandra-engine HOT 7 CLOSED

from django.db import connection
connection.connect()

from django.db import connections
connections['cassandra'].connect()

$ cd django-cassandra-engine/testproject
$ export DJANGO_SETTINGS_MODULE="settings.secondary_cassandra"
$ python manage.py sync_cassandra
Creating keyspace db..
Syncing app.models.ExampleModel
Syncing app.models.ExampleModel2
Syncing app.models.TestProjectModel
$ python manage.py shell
Python 2.7.8 (default, Oct 20 2014, 15:05:19) 
[GCC 4.9.1] on linux2
Type "help", "copyright", "credits" or "license" for more information.
(InteractiveConsole)
>>> from app.models import *
>>> ExampleModel.objects.create(id=1)
ExampleModel(id=1, created_at=None, deleted=False)
>>> list(ExampleModel.objects.all())
[ExampleModel(id=1, created_at=None, deleted=False)]

Django==1.7.7
Jinja2==2.8
Markdown==2.6.2
MarkupSafe==0.23
PyYAML==3.11
argparse==1.2.1
backports.ssl-match-hostname==3.4.0.2
blist==1.3.6
cassandra-driver==3.0.0
certifi==2015.04.28
click==5.1
cqlengine==0.21.0
django-cassandra-engine==0.6.0
djangotoolbox==1.6.2
futures==3.0.3
livereload==2.4.0
mkdocs==0.14.0
mock==1.0.1
six==1.10.0
tornado==4.2.1
wsgiref==0.1.2

[baali@jugaad] [~/analytics/django-cassandra-engine/testproject]
 $ export DJANGO_SETTINGS_MODULE="settings.secondary_cassandra"
(tsenv)[baali@jugaad] [~/analytics/django-cassandra-engine/testproject]
 $ python manage.py sync_cassandra
Creating keyspace db..
Syncing app.models.ExampleModel
Syncing app.models.ExampleModel2
Syncing app.models.TestProjectModel
(tsenv)[baali@jugaad] [~/analytics/django-cassandra-engine/testproject]
 $ python manage.py shell
Python 2.7.6 (default, Mar 22 2014, 22:59:56) 
Type "copyright", "credits" or "license" for more information.

IPython 0.13.2 -- An enhanced Interactive Python.
?         -> Introduction and overview of IPython's features.
%quickref -> Quick reference.
help      -> Python's own help system.
object?   -> Details about 'object', use 'object??' for extra details.

In [1]: from app.models import *

In [2]: ExampleModel.objects.create(id=1)
Out[2]: ExampleModel(id=1, created_at=None, deleted=False)

In [3]: list(ExampleModel.objects.all())
Out[3]: [ExampleModel(id=1, created_at=None, deleted=False)]

 $ pip freeze|grep cass
cassandra-driver==3.0.0
django-cassandra-engine==0.6.0
$ pip freeze | grep Django
Django==1.7.7
$ pip freeze | grep cql
cqlengine==0.21.0