initial impelementation of tearDown unit testing python

I did tried to do the unit testing in flask. And I did, I'm testing a function that saves documents in database. I want to after finishing those testing function to apply tearDown function to delete all the data that were added in database while testing.

How can I do this, I couldn't find help.

from app import create_app, mongo
...

class ApiTestCases(TestCase):

    def create_app(self):
        app = create_app()
        return app

    def setUp(self):
        pass

    def tearDown(self):
        pass

    def test_saving_dummy_json(self):

        json_obj =  {"test": "test", "post_type": "test"}
        response = self.client.post(
            url_for('api.save'),
            data=json.dumps(json_obj),
            content_type='application/json'
        )
        self.assert200(response)

Can somebody help me please? Is any way to do it?

I tried like this by importing mongo

def tearDown(self):
    mongo.session.remove()
    mongo.drop_all()

But this is not working