Exception: No schema for cassandra database

[CharAct3]

My environment:

• python 3.6.2
• django 1.11.4
• django-cassandra-engine 1.2.1

Command python manage.py sync_cassandra worked.
But when I ran python manage.py runserver, it raised an error like this:

Traceback (most recent call last):
  File "/Users/Char/workspace/envs/asgi/lib/python3.6/site-packages/django/utils/autoreload.py", line 228, in wrapper
    fn(*args, **kwargs)
  File "/Users/Char/workspace/envs/asgi/lib/python3.6/site-packages/channels/management/commands/runserver.py", line 55, in inner_run
    self.check_migrations()
  File "/Users/Char/workspace/envs/asgi/lib/python3.6/site-packages/django/core/management/base.py", line 422, in check_migrations
    executor = MigrationExecutor(connections[DEFAULT_DB_ALIAS])
  File "/Users/Char/workspace/envs/asgi/lib/python3.6/site-packages/django/db/migrations/executor.py", line 20, in __init__
    self.loader = MigrationLoader(self.connection)
  File "/Users/Char/workspace/envs/asgi/lib/python3.6/site-packages/django/db/migrations/loader.py", line 52, in __init__
    self.build_graph()
  File "/Users/Char/workspace/envs/asgi/lib/python3.6/site-packages/django/db/migrations/loader.py", line 209, in build_graph
    self.applied_migrations = recorder.applied_migrations()
  File "/Users/Char/workspace/envs/asgi/lib/python3.6/site-packages/django/db/migrations/recorder.py", line 65, in applied_migrations
    self.ensure_schema()
  File "/Users/Char/workspace/envs/asgi/lib/python3.6/site-packages/django/db/migrations/recorder.py", line 57, in ensure_schema
    editor.create_model(self.Migration)
  File "/Users/Char/workspace/django-cassandra-engine/django_cassandra_engine/base/schema.py", line 23, in create_model
    raise Exception('No schema for cassandra database')
Exception: No schema for cassandra database