[Solved] Identify the error in this factory function:def create_app(): app = Flask(__name__) db = SQLAlchemy(app) return app app = create_app() | Flask

Flask - Ecosystem and Patterns

Identify the error in this factory function:

def create_app():
    app = Flask(__name__)
    db = SQLAlchemy(app)
    return app

app = create_app()

AFlask app must be created after SQLAlchemy initialization

BSQLAlchemy should be initialized outside and then bound inside factory

CThe factory function must not return the app

DThere is no error in this code

Step-by-Step Solution

Solution:

Step 1: Recall extension initialization best practice
Extensions like SQLAlchemy should be created outside the factory without app, then initialized with app inside.
Step 2: Analyze the code
Here, SQLAlchemy is initialized with app inside factory, which is not recommended for the factory pattern.
Final Answer:
SQLAlchemy should be initialized outside and then bound inside factory -> Option B
Quick Check:
Extension init best practice = B [OK]

Quick Trick: Create extensions outside, init inside factory [OK]

Common Mistakes:

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