Installing flask-socketio in cookiecutter-flask

Question

I opened a command shell and made pip install flask-socketio . When I added in extensions.py from flask_socketio import SocketIO

I got an error after doing npm start :

Error: While importing 'autoapp', an ImportError was raised:
[FLASK]
[FLASK] Traceback (most recent call last):
[...]
[FLASK]     from flask_socketio import SocketIO
[FLASK] ModuleNotFoundError: No module named 'flask_socketio'

I tried to run the virtual environment manually and install the module but I did not managed to do it. I also tried to uninstall and install.