def METHOD_NAME(self, a_shape, y_shape=None,
                 rowvar=True, bias=False, ddof=None,
                 dtype=None, fweights=None, aweights=None):
    for xp in (numpy, cupy):
        a, y = self.generate_input(a_shape, y_shape, xp, dtype)
        with pytest.raises(ValueError):
            xp.cov(a, y, rowvar, bias, ddof,
                   fweights, aweights, dtype=dtype)