def test_degenerate_mode_nan(self):
        msa = TabularMSA([DNA('NAC'),
                          DNA('NNC')])
        actual = msa.conservation(metric='inverse_shannon_uncertainty',
                                  degenerate_mode='nan')
        expected = np.array([np.nan,
                             np.nan,
                             scipy.stats.entropy([1.0], base=4) - 1.])
        npt.assert_array_equal(actual, expected)
dataset/ETHPy150Open biocore/scikit-bio/skbio/alignment/tests/test_tabular_msa.py/TestConservation.test_degenerate_mode_nan/swapped operands of `-`