我正在尝试卸载名为 的应用程序django-cities，但在我的应用程序“位置”中，我有一个名为 的模型Venue，在迁移中该0001_initial.py模型的ForeingKeytocities.Subregion模型为django-cities。
我继续删除django-cities，INSTALLED_APPS但出现以下错误：
Traceback (most recent call last):
File "/home/d/.virtualenvs/beplay/local/lib/python2.7/site-packages/django/utils/autoreload.py", line 227, in wrapper
fn(*args, **kwargs)
File "/home/d/.virtualenvs/beplay/local/lib/python2.7/site-packages/django/core/management/commands/runserver.py", line 128, in inner_run
self.check_migrations()
File "/home/d/.virtualenvs/beplay/local/lib/python2.7/site-packages/django/core/management/base.py", line 422, in check_migrations
executor = MigrationExecutor(connections[DEFAULT_DB_ALIAS])
File "/home/d/.virtualenvs/beplay/local/lib/python2.7/site-packages/django/db/migrations/executor.py", line 20, in __init__
self.loader = MigrationLoader(self.connection)
File "/home/d/.virtualenvs/beplay/local/lib/python2.7/site-packages/django/db/migrations/loader.py", line 52, in __init__
self.build_graph()
File "/home/d/.virtualenvs/beplay/local/lib/python2.7/site-packages/django/db/migrations/loader.py", line 274, in build_graph
raise exc
django.db.migrations.exceptions.NodeNotFoundError: Migration places.0001_initial dependencies reference nonexistent parent …