python - ImportError when importing two levels up -

i trying import noun0.routes following package structure importerror: cannot import name db. why getting error , how fix it?

├── some_rest_api │   ├── noun0 │   │   ├── __init__.py │   │   ├── models.py │   │   ├── routes.py │   ├── noun1 │   │   ├── __init__.py │   │   ├── models.py │   │   ├── routes.py │   ├── routes.py │   ├── utils.py │   └── __init__.py ├── requirements.txt └── setup.py 

some_rest_api/__init__.py

from flask import flask flask.ext.sqlalchemy import sqlalchemy  noun0.routes import noun0_api  app = flask(__name__) db = sqlalchemy(app) app.register_blueprint(noun0_api) 

some_rest_api/noun0/models.py

from some_rest_api import db 

you've created circular import situation. __init__.py imports noun0.routes, imports noun0.models, tries import db. however, __init__.py hasn't reached point has defined db, it's still trying complete import.

move route imports after definitions (or chain of imports) depend on.

app = flask(__name__) db = sqlalchemy(app)  some_rest_api.noun0.routes import noun0_api  app.register_blueprint(noun0_api) 

this situation mentioned in flask docs @ bottom of page.

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i changed import from noun0.routes from some_rest_api.noun0.routes. using old, error prone pattern of relative imports. behavior removed in python 3. better use absolute imports (as did), or use dot notation relative imports: from .. import db says "go 2 levels am.