Models with inheritance and __json_api_type__ 
Models with inheritance and __json_api_type__ 

I think this line exists today so users can override the __json_api_type__ locally on a specific model.
However, it appears that since the override name is the same as the internal name, if the models are using inheritance the __json_api_type__ only gets set on which ever models get processed first.  Once the base class loads the other models won't set the __json_api_type__. 

The proposed change here would be a breaking change if anyone was overridding the __json_api_type__ directly on their models.
emilecaron/sqlalchemy-jsonapi,ColtonProvias/sqlalchemy-jsonapi,bladams/sqlalchemy-jsonapi