def test_invalid_scalar_index(adata, index):
    # https://github.com/theislab/anndata/issues/619
    with pytest.raises(IndexError, match=r".*index.* out of range\."):
        _ = adata[index]
def i1beta_up(i1, beta, up, ax=0):
    """creates a surface plot of up vs i1, beta"""
    if ax == 0:
        _create_3d_axis()
        ax = plt.gca()
    _plot_surface(ax, i1, beta, up,
                  (u'I1/A', u'Beta/°', u'Up/V'),
                  azim=60)