Solution
app = Flask(__name__)
app.config['SECRET_KEY'] = 'this is my secret key'
app.config['SQLALCHEMY_DATABASE_URI'] = 'mysql+pymysql://root:admin@127.0.0.1:3306/flask_practice_2'
app.config['SQLALCHEMY_TRACK_MODIFICATIONS'] = False
db = SQLAlchemy(app)
migrate = Migrate(app, db)