MONGO AGGREGATION FRAMEWORK

@app.route('/seepati', methods=['POST', 'GET'])
def seepati():
    if 'username' in session:
        muser = session['username']
        b = mongo.db.b
        pipeline = b.aggregate([
            {'$match':{'username': muser}},
            {'$lookup':{'from': 'a', 'localField': 'username', 'foreignField': 'username', 'as': 'arranjofinal'}}
            {'$sort':{'username': 1}}
        ])
        return pipeline
    return render_template('index.html')