import error for CROWNBurgersVerifier

[ddg93]

Installed with the setup.py, but when doing:
from pinn_verifier.burgers import CROWNBurgersVerifier
I get:
ModuleNotFoundError: No module named 'tools'
which refers to the following line within /pinn_verifier/crown.py:10

from tools.custom_torch_modules import Add, Mul

Looks like an external package not specified in the requirements? What am I missing?
Thanks