AttributeError: 'str' object has no attribute '_meta'

[ElijahAhianyo]

so im using django 3.1 and i defined a model with a foreign key relation like this:

class Account(TimeStampedModel):
    corporate = models.ForeignKey('CompanyDetail',on_delete=models.CASCADE,related_name= 'corporate_accounts')
    balance = models.DecimalField(max_digits=20, decimal_places=2)

this throwns an this error when I try to run the project or run migrations:

Watching for file changes with StatReloader
Exception in thread django-main-thread:
Traceback (most recent call last):
  File "/usr/lib/python3.6/threading.py", line 916, in _bootstrap_inner
    self.run()
  File "/usr/lib/python3.6/threading.py", line 864, in run
    self._target(*self._args, **self._kwargs)
  File "/home/zeus-of-python/.virtualenv/lib/python3.6/site-packages/django/utils/autoreload.py", line 53, in wrapper
    fn(*args, **kwargs)
  File "/home/zeus-of-python/.virtualenv/lib/python3.6/site-packages/django/core/management/commands/runserver.py", line 109, in inner_run
    autoreload.raise_last_exception()
  File "/home/zeus-of-python/.virtualenv/lib/python3.6/site-packages/django/utils/autoreload.py", line 76, in raise_last_exception
    raise _exception[1]
  File "/home/zeus-of-python/.virtualenv/lib/python3.6/site-packages/django/core/management/__init__.py", line 357, in execute
    autoreload.check_errors(django.setup)()
  File "/home/zeus-of-python/.virtualenv/lib/python3.6/site-packages/django/utils/autoreload.py", line 53, in wrapper
    fn(*args, **kwargs)
  File "/home/zeus-of-python/.virtualenv/lib/python3.6/site-packages/django/__init__.py", line 24, in setup
    apps.populate(settings.INSTALLED_APPS)
  File "/home/zeus-of-python/.virtualenv/lib/python3.6/site-packages/django/apps/registry.py", line 122, in populate
    app_config.ready()
  File "/home/zeus-of-python/.virtualenv/lib/python3.6/site-packages/jet_django/apps.py", line 12, in ready
    conf = JetDjangoConfiguration()
  File "/home/zeus-of-python/.virtualenv/lib/python3.6/site-packages/jet_django/configuration.py", line 28, in __init__
    self.models = dict(map(lambda x: (self.model_key(x), self.serialize_model(x)), models))
  File "/home/zeus-of-python/.virtualenv/lib/python3.6/site-packages/jet_django/configuration.py", line 28, in <lambda>
    self.models = dict(map(lambda x: (self.model_key(x), self.serialize_model(x)), models))
  File "/home/zeus-of-python/.virtualenv/lib/python3.6/site-packages/jet_django/configuration.py", line 185, in serialize_model
    'fields': list(map(lambda field: self.serialize_field(field), fields))
  File "/home/zeus-of-python/.virtualenv/lib/python3.6/site-packages/jet_django/configuration.py", line 185, in <lambda>
    'fields': list(map(lambda field: self.serialize_field(field), fields))
  File "/home/zeus-of-python/.virtualenv/lib/python3.6/site-packages/jet_django/configuration.py", line 214, in serialize_field
    result['params'] = {'related_model': self.serialize_related_model(field.related_model)}
  File "/home/zeus-of-python/.virtualenv/lib/python3.6/site-packages/jet_django/configuration.py", line 250, in serialize_related_model
    'model': Model._meta.db_table,
AttributeError: 'str' object has no attribute '_meta'

everything works fine when I manually import CompanyDetail. It also works fine when I take out jet_django from my installed apps in settings.py and urls.py file.