class Billing(EmbeddedModel):
    ...

class PatientRecord(EmbeddedModel):
    billing = EmbeddedModelField(Billing)

class Patient(models.Model):
    patient_record = EmbeddedModelField(PatientRecord)

$ python manage.py migrate emb
Operations to perform:
  Apply all migrations: emb
Running migrations:
  Applying emb.0001_initial...Traceback (most recent call last):
  File "/home/tim/code/mysite/manage.py", line 10, in <module>
    execute_from_command_line(sys.argv)
  File "/home/tim/code/django/django/core/management/__init__.py", line 443, in execute_from_command_line
    utility.execute()
  File "/home/tim/code/django/django/core/management/__init__.py", line 437, in execute
    self.fetch_command(subcommand).run_from_argv(self.argv)
  File "/home/tim/code/django/django/core/management/base.py", line 420, in run_from_argv
    self.execute(*args, **cmd_options)
  File "/home/tim/code/django/django/core/management/base.py", line 464, in execute
    output = self.handle(*args, **options)
             ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/home/tim/code/django/django/core/management/base.py", line 111, in wrapper
    res = handle_func(*args, **kwargs)
          ^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/home/tim/code/django/django/core/management/commands/migrate.py", line 354, in handle
    post_migrate_state = executor.migrate(
                         ^^^^^^^^^^^^^^^^^
  File "/home/tim/code/django/django/db/migrations/executor.py", line 137, in migrate
    state = self._migrate_all_forwards(
            ^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/home/tim/code/django/django/db/migrations/executor.py", line 169, in _migrate_all_forwards
    state = self.apply_migration(
            ^^^^^^^^^^^^^^^^^^^^^
  File "/home/tim/code/django/django/db/migrations/executor.py", line 257, in apply_migration
    state = migration.apply(state, schema_editor)
            ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/home/tim/code/django/django/db/migrations/migration.py", line 132, in apply
    operation.database_forwards(
  File "/home/tim/code/django/django/db/migrations/operations/models.py", line 100, in database_forwards
    schema_editor.create_model(model)
  File "/home/tim/code/django-mongodb/django_mongodb_backend/query.py", line 20, in wrapper
    return func(*args, **kwargs)
           ^^^^^^^^^^^^^^^^^^^^^
  File "/home/tim/code/django-mongodb/django_mongodb_backend/schema.py", line 29, in wrapper
    func(self, model, *args, **kwargs)
  File "/home/tim/code/django-mongodb/django_mongodb_backend/schema.py", line 48, in create_model
    self._create_collection(model)
  File "/home/tim/code/django-mongodb/django_mongodb_backend/schema.py", line 455, in _create_collection
    if model_has_encrypted_fields(model):
       ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/home/tim/code/django-mongodb/django_mongodb_backend/utils.py", line 160, in model_has_encrypted_fields
    return any(
           ^^^^
  File "/home/tim/code/django-mongodb/django_mongodb_backend/utils.py", line 164, in <genexpr>
    and model_has_encrypted_fields(field.embedded_model)
        ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/home/tim/code/django-mongodb/django_mongodb_backend/utils.py", line 166, in model_has_encrypted_fields
    for field in model._meta.fields
                 ^^^^^^^^^^^
AttributeError: 'str' object has no attribute '_meta'