The code snippet does not change anything from cache.
It just uses some weight parameters and reads them in w.data = weights[i] * ....
If you would change something in weights, the state dict would also reference this change:
model = nn.Linear(1, 1)
state_dict = model.state_dict()
w = [value for (key, value) in state_dict.items()]
w[-1][0] = -10000.
print(w)
> [tensor([[-0.2974]]), tensor([-10000.])]
print(state_dict)
> OrderedDict([('weight', tensor([[-0.2974]])), ('bias', tensor([-10000.]))])