def test_source_keys_reset_between_validations():
        """
        Ensure that calling validate with source_keys=None resets to default keys.
        """
        schema_filter = {'model': 'tests.models.Company', 'filter': {'foo': 'bar'}}
        schema_data = {'model': 'tests.models.Company', 'data': {'foo': 'bar'}}
    
        # Default behavior should accept filter
>       assert SchemaValidator.validate(schema_filter) is None

sqlalchemyseed/grader_tests/test_validator_more.py:36: 
_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ 
sqlalchemyseed/validator.py:128: in validate
    cls._pre_validate(entities, is_parent=True, ref_prefix=ref_prefix)
sqlalchemyseed/validator.py:142: in _pre_validate
    return cls._validate(entities, is_parent, ref_prefix)
sqlalchemyseed/validator.py:158: in _validate
    check_model_key(entity, entity_is_parent)
_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ 

entity = {'filter': {'foo': 'bar'}, 'model': 'tests.models.Company'}
entity_is_parent = True

    def check_model_key(entity: dict, entity_is_parent: bool):
        model = Key.model()
        if model not in entity and entity_is_parent:
>           raise errors.MissingRequiredKeyError("'model' key is missing.")
E           sqlalchemyseed.errors.MissingRequiredKeyError: 'model' key is missing.

sqlalchemyseed/validator.py:71: MissingRequiredKeyError