def METHOD_NAME():
    # input am
    relative_am = np.array([nan, 40, 2, .999])
    # call without pressure kwarg
    out = atmosphere.get_absolute_airmass(relative_am)
    expected = np.array([nan, 40., 2., 0.999])
    assert_allclose(out, expected, equal_nan=True, atol=0.001)
    # call with pressure kwarg
    out = atmosphere.get_absolute_airmass(relative_am, pressure=90000)
    expected = np.array([nan, 35.529, 1.776, 0.887])
    assert_allclose(out, expected, equal_nan=True, atol=0.001)