def test_drop_obs_column():
    adata = ad.AnnData(np.array(X_list), obs=obs_dict, dtype="int32")

    subset = adata[:2]
    assert subset.is_view
    # returns a copy of obs
    assert subset.obs.drop(columns=["oanno1"]).columns.tolist() == ["oanno2", "oanno3"]
    assert subset.is_view
    # would modify obs, so it should actualize subset and not modify adata
    subset.obs.drop(columns=["oanno1"], inplace=True)
    assert not subset.is_view
    assert subset.obs.columns.tolist() == ["oanno2", "oanno3"]

    assert adata.obs.columns.tolist() == ["oanno1", "oanno2", "oanno3"]
def i1beta_psiq(i1, beta, psiq, ax=0):
    """creates a surface plot of psiq vs i1, beta"""
    if ax == 0:
        _create_3d_axis()
        ax = plt.gca()
    azim = 210
    if 0 < np.mean(beta) or -90 > np.mean(beta):
        azim = -60
    _plot_surface(ax, i1, beta, psiq,
                  (u'I1/A', u'Beta/°', u'Psi q/Vs'),
                  azim=azim)