def test_set_obs(adata, subset_func):
    init_hash = joblib.hash(adata)

    subset = adata[subset_func(adata.obs_names), :]

    new_obs = pd.DataFrame(
        dict(a=np.ones(subset.n_obs), b=np.ones(subset.n_obs)),
        index=subset.obs_names,
    )

    assert subset.is_view
    subset.obs = new_obs
    assert not subset.is_view
    assert np.all(subset.obs == new_obs)

    assert joblib.hash(adata) == init_hash
def days_till_due(self):
        """
        Returns the number of days till the due date. Returns a negative number
        of days when the due date is in the past.
        Returns 0 when the task has no due date.
        """
        due = self.due_date()
        if due:
            diff = due - date.today()
            return diff.days
        return 0