How to slove the problem: "'Tensor' object has no attribute 'btrifact'"

Recent, I am studying the LU factorization, however, I met a issue as following:
w = torch.randn(3,3)
w = w.unsqueeze(0).btrifact()
AttributeError: ‘Tensor’ object has no attribute ‘btrifact’
how to solve above issue?

btrifact is renamed to lu