Fossen

`SQLAlchemy.__repr__` raises `KeyError` when the default engine is not set.

1

```python from flask import Flask from flask_sqlalchemy import SQLAlchemy db = SQLAlchemy() app = Flask(__name__) app.config['SQLALCHEMY_BINDS'] = {'x': 'sqlite:///:memory:'} db.init_app(app) with app.app_context(): print(db) # KeyError: None ``` Environment: - Python...