Flask app returning 500 scenarios when using SQLAlchemy with PostgreSQL and async/await
I'm experimenting with I'm confused about I'm working with a 500 Internal Server behavior when trying to use SQLAlchemy with an async Flask app. I've set up my Flask application with `flask-sqlalchemy` and `asyncpg` for PostgreSQL, and I'm utilizing `async/await` syntax in my route handlers. However, when I attempt to access a specific endpoint, the server throws an behavior: `TypeError: 'NoneType' object is not callable`. Here's a minimal example of how I structured my code: ```python from flask import Flask, jsonify from flask_sqlalchemy import SQLAlchemy from sqlalchemy.ext.asyncio import create_async_engine, AsyncSession from sqlalchemy.orm import sessionmaker import asyncio app = Flask(__name__) app.config['SQLALCHEMY_DATABASE_URI'] = 'postgresql+asyncpg://user:password@localhost/dbname' app.config['SQLALCHEMY_TRACK_MODIFICATIONS'] = False db = SQLAlchemy(app) async def get_async_session(): engine = create_async_engine(app.config['SQLALCHEMY_DATABASE_URI'], future=True, echo=True) async_session = sessionmaker(engine, expire_on_commit=False, class_=AsyncSession) async with async_session() as session: yield session @app.route('/users', methods=['GET']) async def get_users(): async for session in get_async_session(): result = await session.execute('SELECT * FROM users') users = result.scalars().all() return jsonify(users) if __name__ == '__main__': app.run(debug=True) ``` I’ve tried various combinations of `async` and `await`, and even experimented with synchronous session creation, but the behavior continues. I also checked my database connection and it works fine when using synchronous routes. When I run the app, the console shows the behavior stack trace, pointing to the line where `async for session in get_async_session()` is called. I suspect that the scenario might be related to how I'm managing the async session context. Any insights on how to resolve this scenario would be greatly appreciated! I recently upgraded to Python 3.10. Hoping someone can shed some light on this. What would be the recommended way to handle this? Has anyone dealt with something similar?