hyperseti/normalize.py:55 reports an attribute error related to cupy

[texadactyl]

Gross symptoms from pytest: FAILED test/test_normalize.py::test_normalize_bandpass - AttributeError: module 'cupy' has no attribute 'polyfit' FAILED test/test_normalize.py::test_normalize_multi_if - AttributeError: module 'cupy' has no attribute 'polyfit'

        if poly_fit > 0:
            # WAR: int64 dtype causes issues in cupy 10 (19.04.2022)

          p    = cp.poly1d(cp.polyfit(xc, dfit, poly_fit))

E AttributeError: module 'cupy' has no attribute 'polyfit'

It also causes issues in cupy 8.6.0 at the BL data centre.

[texadactyl]

Verified fixed using cupy 9.0.0.