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 delete_category(category_id):
    category = Category.query.filter_by(id=category_id).first_or_404()

    involved_users = User.query.filter(Forum.category_id == category.id,
                                       Topic.forum_id == Forum.id,
                                       Post.user_id == User.id).all()

    category.delete(involved_users)
    flash(_("Category with all associated forums deleted."), "success")
    return redirect(url_for("management.forums"))