Unresolved reference issue in PyCharm

I have a directory structure

├── simulate.py
├── src
│   ├── networkAlgorithm.py
│   ├── ...

And I can access the network module with sys.path.insert().

import sys
import os.path
sys.path.insert(0, "./src")
from networkAlgorithm import *

However, pycharm complains that it cannot access the module. How can I teach pycham to resolve the reference?

from Unresolved reference issue in PyCharm